API marketplace

Machining cutting-speed and feed maths as an API, computed locally and deterministically. The speed endpoint converts between cutting (surface) speed and spindle rpm for a given tool or workpiece diameter, in both directions and in either unit system: metric uses N = Vc·1000/(π·D) with Vc in metres per minute and D in millimetres, and imperial uses RPM = SFM·12/(π·D) with the surface speed in feet per minute and the diameter in inches. The feed endpoint computes the table feed rate from the feed per tooth (chip load), the number of teeth or flutes and the spindle rpm for milling (feed = fz·z·N), or from the feed per revolution for turning and drilling, and reports it in millimetres or inches per minute. The materials endpoint lists typical carbide cutting speeds by material, from aluminium and brass through mild and stainless steel to titanium, with a note to use about a third for HSS tooling. Everything is computed locally and deterministically, so it is instant and private. An indicative aid — always confirm with the tool maker's data and adjust for depth of cut, coolant and rigidity. Ideal for CNC and machine-shop tools, CAM and feeds-and-speeds apps, maker and hobby machining, and manufacturing calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is machining feeds and speeds; for screw-thread pitch and tap drill use a thread API and for bolt-circle layouts use a bolt-circle API.

Uptime

100.0%

Latency

74ms

Subs

3,761

Bolt-circle (bolt pattern / PCD) geometry as an API, computed locally and deterministically. The coordinates endpoint lays out a set of equally spaced holes on a circle: from the bolt-circle diameter (or radius), the number of holes, an optional start angle, centre offset and direction, it returns the X and Y coordinate and angle of every hole, the angular step (360 ÷ number of holes) and the chord between adjacent holes — exactly what a CNC or drawing needs. The chord endpoint gives the straight-line distance between any two holes on the pattern using chord = 2·R·sin(central angle ÷ 2), taking the shorter way around. The diameter endpoint works in reverse: from a measured distance between two holes and the number of holes it recovers the bolt-circle diameter, so you can reverse-engineer an existing flange or wheel. Lengths are unit-agnostic — the output is in whatever unit you supply. Everything is computed locally and deterministically, so it is instant and private. Ideal for CNC and CAD tools, machining and fabrication apps, flange, wheel and hub design, and drilling-jig and robotics projects. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is bolt-circle geometry; for screw-thread pitch and tap drill use a thread API and for spur-gear geometry use a gear API.

Uptime

100.0%

Latency

79ms

Subs

3,817

Spur-gear geometry as an API, computed locally and deterministically for standard full-depth involute teeth. The geometry endpoint takes a module and a number of teeth (and an optional pressure angle, default 20°) and returns the complete tooth geometry: the pitch diameter (module × teeth), the base, tip (outside) and root diameters, the addendum, dedendum, whole and working depth, the circular and base pitch, the diametral pitch and the tooth thickness — all in millimetres. The module can be given directly or derived from a diametral pitch or a circular pitch. The pair endpoint meshes two gears of the same module and returns each gear's pitch and tip diameter, the centre distance (module × (z1 + z2) ÷ 2) and the gear ratio. The module endpoint converts freely between module, diametral pitch and circular pitch, or derives the module from a pitch diameter and tooth count. Everything is computed locally and deterministically, so it is instant and private. Ideal for machine-design and CAD tools, gear and gearbox calculators, maker, robotics and 3D-printing projects, and mechanical-engineering apps. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is spur-gear geometry; for bicycle gear ratios and development use a bike-gear API and for belt-and-pulley drives use a belt-drive API.

Uptime

100.0%

Latency

77ms

Subs

4,957

Pump power, head and affinity maths as an API, computed locally and deterministically. The power endpoint computes the power a pump needs from its flow rate, head, fluid density and efficiency: the hydraulic (water) power is ρ·g·Q·H, the shaft (brake) power is that divided by the pump efficiency, and an optional motor efficiency gives the electrical input power — all reported in watts, kilowatts and horsepower. Flow accepts litres per second or minute, cubic metres per hour or second and US gallons per minute; head accepts metres or feet; and the fluid can be water, seawater, oil, diesel and more, or a custom density. The head endpoint converts between pressure and head of fluid, H = P/(ρ·g), in both directions, across pascals, kPa, bar, psi and atmospheres. The affinity endpoint applies the pump affinity laws — flow scales with speed, head with speed squared and power with speed cubed — to predict the new operating point when you change the pump speed or trim the impeller diameter. Everything is computed locally and deterministically, so it is instant and private. Ideal for plumbing and HVAC tools, process and water-treatment engineering, irrigation and pool-pump apps, and energy-efficiency calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is pump power and head maths; for flow rate from pipe diameter and velocity use a pipe-flow API and for open-channel flow use a Manning API.

Uptime

100.0%

Latency

82ms

Subs

4,386

Screw-thread geometry as an API, computed locally and deterministically for the 60° ISO metric and Unified (UTS) thread form. The pitch endpoint converts between the thread pitch in millimetres and threads per inch (TPI = 25.4 ÷ pitch) and works out the lead — the distance the thread advances in one turn — from the pitch and the number of starts. The dimensions endpoint takes a nominal (major) diameter and a pitch and returns the full set of thread diameters and heights: the fundamental triangle height, the external thread height, the pitch diameter (D − 0.6495·P), the external minor diameter (D − 1.2269·P) and the internal minor diameter (D − 1.0825·P), in both millimetres and inches. The tapdrill endpoint gives the drill size for cutting an internal thread: the standard metric rule of nominal diameter minus pitch (about 75–83% thread), the resulting thread engagement, and — for a target engagement percentage — the matching drill size. Diameters accept millimetres or inches, and threads can be specified by pitch or by TPI. Everything is computed locally and deterministically, so it is instant and private. Ideal for machining and CNC tools, mechanical-design and CAD apps, maker and 3D-printing projects, and hardware and fastener catalogues. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is screw-thread geometry; for the torque to tighten a bolt use a torque API.

Uptime

100.0%

Latency

82ms

Subs

4,083

Belt-drive and pulley maths as an API, computed locally and deterministically. The belt endpoint computes the length of an open V-belt or flat belt from the two pulley diameters and the centre distance with L = 2C + (π/2)(D1+D2) + (D1−D2)²/(4C), and returns the belt length plus the wrap (contact) angle on each pulley; pass a driver rpm and it also gives the belt surface speed. The ratio endpoint computes the speed ratio of a pulley pair (driven ÷ driver diameter, since N1·D1 = N2·D2): give a driver or driven rpm and it returns the other, the torque ratio and the belt speed. The centers endpoint reverses the length equation to find the centre distance for a target belt length, solving the equation numerically. Diameters and distances accept millimetres, centimetres, metres, inches or feet, and lengths are reported in several units. Everything is computed locally and deterministically, so it is instant and private. Ideal for machine and drivetrain design tools, maintenance and MRO apps, maker and CNC projects, and mechanical-engineering calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is belt-and-pulley power transmission; for bicycle gear ratios and development use a bike-gear API and for bolt tightening torque use a torque API.

Uptime

100.0%

Latency

77ms

Subs

4,956

Rigging and lifting load maths as an API, computed locally and deterministically. The wll endpoint relates the working load limit to the minimum breaking strength through the safety (design) factor: give a breaking strength and it returns the working load limit (WLL = MBS ÷ safety factor), or give a working load limit and it returns the minimum breaking strength your hardware must be rated for (MBS = WLL × safety factor). The safety factor can be given directly or looked up by component — general rigging and wire rope 5, chain sling 4, shackle 6, personnel/man-rated 10. The sling endpoint computes the tension in each leg of a multi-leg sling as the lifting angle changes: because the legs pull at an angle, each carries more than its share, with a load factor of 1/sin(angle to horizontal) — 1.0 vertical, 1.15 at 60°, 1.41 at 45° and 2.0 at 30° — and it accepts the angle from horizontal, from vertical or the included angle between legs. The safety endpoint lists the typical design factors. Loads are given in kilograms, pounds, tonnes, kilonewtons or newtons and reported in all of them. Everything is computed locally and deterministically, so it is instant and private. A planning aid, not a substitute for a qualified rigger or the governing standard (ASME B30, EN, local code). Ideal for crane and lifting apps, construction and warehouse tools, theatrical and entertainment rigging, and towing and recovery calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is rigging load maths; for the weight of the steel being lifted use a metal-weight API.

Uptime

100.0%

Latency

81ms

Subs

4,843

Open-channel flow maths as an API, computed locally and deterministically with the Manning equation. The flow endpoint computes the discharge and velocity of water in an open channel — rectangular, trapezoidal, triangular or circular (a part-full pipe) — from the flow depth, the channel dimensions, the channel slope and the Manning roughness coefficient n: it works out the flow area, the wetted perimeter and the hydraulic radius, then applies Q = (1/n)·A·R^(2/3)·S^(1/2) and V = Q/A, reporting the discharge in cubic metres per second and hour, litres per second, cubic feet per second and US gallons per minute. The normal-depth endpoint reverses it: given a target discharge it solves for the normal depth by bisection and returns the resulting area, velocity and a discharge check. The roughness endpoint is a reference of typical Manning n values, from smooth PVC (0.009) and concrete (0.013) through earth and gravel to rocky natural streams (0.05); pass a material name or an explicit n. Dimensions are metric (metres by default, or cm, mm, ft, in). Everything is computed locally and deterministically, so it is instant and private. Ideal for civil and drainage engineering tools, stormwater and culvert design, irrigation and hydrology apps, and environmental modelling. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is open-channel (Manning) hydraulics; for full-pipe flow rate from diameter and velocity use a pipe-flow API.

Uptime

100.0%

Latency

81ms

Subs

3,289

Septic-system sizing as an API, computed locally and deterministically with the typical US onsite-wastewater rules of thumb. The flow endpoint estimates the design wastewater flow for a home from its number of bedrooms (assuming two people per bedroom) or an explicit occupancy, at a default 60 gallons per person per day, returning the daily flow in US gallons and litres. The tank endpoint recommends a septic tank size as the larger of a retention-based size (flow × retention days, default two days) and the typical bedroom-based code minimum (≤3 bedrooms 1,000, 4 bedrooms 1,200, 5 bedrooms 1,500, 6 bedrooms 2,000 US gallons), and tells you which one governs. The drainfield endpoint sizes the soil absorption (leach) field: it divides the daily flow by a soil loading rate — given directly or looked up from a percolation rate in minutes per inch — to get the absorption area, then divides by the trench width to get the trench length, in both imperial and metric. Everything is computed locally and deterministically, so it is instant and private. An estimating aid, not a code-stamped design — always confirm with your local health authority. Ideal for plumbing and septic-installer tools, rural real-estate and land apps, home-building and permitting calculators, and inspection software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is septic / onsite-wastewater sizing; for storage-tank volume and fill level use a tank API.

Uptime

100.0%

Latency

79ms

Subs

4,552

Roof snow-load maths as an API, computed locally and deterministically using the ASCE 7 method. The roof endpoint turns a ground snow load into the design roof snow load: the flat-roof load is pf = 0.7 · Ce · Ct · Is · pg, using the exposure, thermal and importance factors, and the sloped-roof load is ps = Cs · pf, where the slope factor Cs follows the warm-roof all-surfaces curve (1.0 up to 30°, falling linearly to 0 at 70°) or a value you supply. It reports every load in kilopascals, pascals, pounds per square foot and kilograms per square metre, and — if you give a roof area — the total load in kilonewtons, kilograms, tonnes and pounds. The depth endpoint converts a measured snow depth and a density (given directly or by snow type, from fresh ~100 to ice ~917 kg/m³) into a load. The convert endpoint converts a snow load between kPa, psf, kg/m², Pa and psi. Depths accept millimetres, centimetres, metres, inches or feet. Everything is computed locally and deterministically, so it is instant and private. An engineering aid, not a code-stamped design — always confirm against the governing local code with a qualified engineer. Ideal for structural and roofing tools, building-code and permitting apps, solar-install and carport planners, and winter-risk calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is roof snow-load engineering; for roof pitch and area geometry use a roofing API and for beam reactions use a beam API.

Uptime

100.0%

Latency

74ms

Subs

4,309

Plant-spacing and planting-density maths as an API, computed locally and deterministically. The grid endpoint works out how many plants fill an area in a square (rectangular) layout: from a spacing (one value, or separate row and in-row spacings) and either an area or a length and width, it returns the planting density per square metre, square foot, 1,000 ft², acre and hectare, an area-based plant estimate, and — when you give length and width — an exact edge-inclusive grid count with the number of rows and plants per row. The triangular endpoint does the same for an offset (hexagonal) layout, where rows sit spacing × √3/2 apart and fit about 15.47 % more plants than a square grid at the same spacing, and it reports the gain. The density endpoint converts a spacing into a planting density in several units, or works in reverse: give a number of plants and an area and it recommends the spacing that fills it. Lengths accept millimetres, centimetres, metres, inches or feet; area accepts m², ft², acres or hectares. Everything is computed locally and deterministically, so it is instant and private. Ideal for gardening and landscaping apps, agriculture and horticulture tools, nursery and farm planners, and reforestation calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is planting layout and density; for fertilizer application rates use a fertilizer API and for mulch, soil and gravel quantities use a landscaping API.

Uptime

100.0%

Latency

77ms

Subs

3,143

Metal stock weight and cost as an API, computed locally and deterministically. The weight endpoint computes the mass of a length of metal stock from its shape, dimensions and material: round bar, square bar, flat bar or plate, sheet, hexagonal bar, round tube or pipe and rectangular (box) tube. It works out the cross-sectional area, multiplies by the length and the material density, and returns the weight per piece and the total for a quantity — in kilograms, pounds, grams and tonnes — along with the volume. Material density is looked up from a built-in table of metals (steel, stainless, aluminium, copper, brass, bronze, lead, zinc, titanium, nickel, gold, silver and more) or you can pass an explicit density. The cost endpoint multiplies that weight by a price per kilogram, pound or tonne to give the material cost per piece and in total. The materials endpoint lists the densities. Dimensions accept millimetres, centimetres, metres, inches or feet. Everything is computed locally and deterministically, so it is instant and private. Ideal for metal fabrication and machine-shop tools, engineering and CAD apps, scrap and stock quoting, and shipping-weight estimates. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is metal stock weight from geometry and density; for beam reactions and deflection use a beam API and for live metal spot prices use a commodities API.

Uptime

100.0%

Latency

75ms

Subs

4,365

TV and projector viewing-distance maths as an API, computed locally and deterministically. The distance endpoint takes a screen diagonal (inches or centimetres) and aspect ratio and returns the screen width and height and the recommended seating distance for each standard — SMPTE's 30° minimum viewing angle (the farthest comfortable seat), THX's 36° recommendation and THX's 40° maximum (the closest) — in inches, feet, centimetres and metres, plus an overall recommended range. Pass a resolution (720p, 1080p, 1440p, 4K or 8K) and it also gives the pixel-acuity distance, the point beyond which a 20/20 viewer can no longer resolve individual pixels, so moving closer stops adding detail. The screensize endpoint reverses it: from a seating distance it recommends the screen diagonal for each standard. The fov endpoint gives the horizontal field of view for a screen at a distance, with a verdict on whether it falls in the recommended range. The geometry is exact: width = diagonal × aspect-width / hypot(aspect), and distance = (width/2) / tan(angle/2). Everything is computed locally and deterministically, so it is instant and private. Ideal for home-theatre and AV apps, TV and monitor retail tools, room and seating planners, and AV-installer calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is viewing-distance geometry; for pixel density (PPI) from a resolution use a PPI API.

Uptime

100.0%

Latency

82ms

Subs

3,722

Laboratory dilution and molarity maths as an API, computed locally and deterministically. The dilution endpoint solves the standard C1·V1 = C2·V2 relation: give any three of the stock concentration, stock volume, final concentration and final volume and it returns the fourth, plus the volume of stock needed, the diluent to add (V2 − V1) and the dilution factor — and it warns you if the numbers would concentrate rather than dilute. The molarity endpoint ties together moles, molarity, volume, mass and molar mass via moles = molarity × volume(L) and mass = moles × molar mass: pass any sufficient subset (for example a target molarity, volume and molar mass) and it returns how much solute you need, with volumes in litres and millilitres and mass in grams and milligrams. The serial endpoint builds a serial-dilution series from a stock concentration, a dilution factor and a number of steps, giving the concentration at each tube and — if you pass a per-tube total volume — the transfer and diluent volumes for each step. Volumes accept litres, millilitres, centilitres, decilitres and microlitres; mass accepts grams, kilograms, milligrams and micrograms. Everything is computed locally and deterministically, so it is instant and private. Ideal for chemistry and biology lab tools, LIMS and bench apps, education and homework helpers, and pharmacy and pipetting calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is a dilution and molarity calculator; for chemical-compound data and properties use a chemistry API and for the ideal gas law use a gas-law API.

Uptime

100.0%

Latency

74ms

Subs

3,253

Beam statics as an API, computed locally and deterministically. The simply-supported endpoint analyses a beam on two supports under a point load (anywhere along the span) or a uniformly distributed load: it returns the support reactions, the maximum shear and the maximum bending moment with its location, and — if you pass the Young's modulus E and second moment of area I — the maximum deflection. The cantilever endpoint does the same for a beam fixed at one end, returning the reaction force and fixing moment, the maximum bending moment and the free-end deflection. The section endpoint gives the cross-section properties that those deflections need: the second moment of area (moment of inertia) and the section modulus for a rectangle, a solid circle or a hollow circular pipe. Every result lists the formula used, so you can show your working. Use consistent units — in SI, load in newtons, distributed load in N/m, lengths in metres, E in pascals and I in m⁴ give moments in N·m and deflections in metres. Everything is computed locally and deterministically, so it is instant and private. Linear-elastic, small-deflection theory — a learning and estimating tool, not a substitute for a qualified structural engineer on a real design. Ideal for engineering and architecture tools, education and physics apps, maker and DIY calculators, and CAD helpers. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is structural beam statics; for bolt and fastener torque use a torque API.

Uptime

100.0%

Latency

81ms

Subs

4,680

Wind-turbine power maths as an API, computed locally and deterministically. The power endpoint applies the wind-power equation P = ½ · ρ · A · v³ · Cp: from the wind speed, the rotor (given as swept area, diameter or blade length) and an optional air density and power coefficient, it returns the total power in the wind, the Betz maximum (the theoretical 16/27 ≈ 59.3 % limit) and the power actually extracted at the chosen coefficient — in watts, kilowatts, megawatts and horsepower. The energy endpoint multiplies power by time and an optional capacity factor to give the energy produced in watt-, kilowatt- and megawatt-hours, taking the power directly or deriving it from the wind and rotor. The sweptarea endpoint is a geometry helper: swept area from a diameter, radius or blade length, plus the blade-tip speed and tip-speed ratio from an rpm. Wind speed accepts metres per second, km/h, mph or knots; air density defaults to 1.225 kg/m³ at sea level. Because power scales with the cube of wind speed and the square of rotor diameter, small changes move it a lot — the API shows every intermediate value. Everything is computed locally and deterministically, so it is instant and private. Ideal for renewable-energy and engineering tools, education and physics apps, site-assessment and feasibility calculators, and STEM projects. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is wind-turbine power physics; for the Beaufort wind scale use a wind-scale API and for solar arrays use a solar API.

Uptime

100.0%

Latency

90ms

Subs

3,758

Rainwater-harvesting maths as an API, computed locally and deterministically. The harvest endpoint works out how much water a roof collects from a given rainfall — from the catchment (roof plan) area, the rainfall depth and a runoff coefficient it returns the harvested volume in litres, US and UK gallons and cubic metres, using the identity that 1 mm of rain over 1 m² collects 1 litre before losses. The runoff coefficient can be given directly or looked up from the roof type (smooth metal collects the most at ~0.9, green roofs the least at ~0.3). The demand endpoint sizes a storage tank from a daily demand (given directly or as people × litres per person) and the length of the dry spell you want to cover, and — if you also pass the annual rainfall and roof area — checks whether a year of harvest can meet a year of demand. The firstflush endpoint sizes a first-flush diverter, the volume of dirty initial rain to discard. Areas accept square metres or square feet (or length × width), rainfall accepts millimetres, centimetres or inches. Everything is computed locally and deterministically, so it is instant and private. Ideal for sustainability and off-grid apps, plumbing and landscaping tools, smart-home water systems, and construction planners. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 4 endpoints. This is rainwater catchment maths; for roof pitch and area geometry use a roofing API and for general construction material quantities use a construction API.

Uptime

100.0%

Latency

73ms

Subs

4,799

Pythagorean numerology as an API, computed locally and deterministically. The lifepath endpoint takes a birth date and returns the Life Path number — the single most important number in numerology — by reducing the month, day and year and summing them, with the master numbers 11, 22 and 33 preserved, and it also gives the Birthday number. The name endpoint maps the letters of a name to digits (A=1…I=9, repeating) and returns the Expression (Destiny) number from all letters, the Soul Urge (Heart's Desire) from the vowels, and the Personality number from the consonants, with a full per-letter breakdown. The personal endpoint forecasts the Personal Year, Personal Month and Personal Day for any target date from a birth month and day. Every number comes with its classic meaning, the raw total and the full reduction chain so you can show your working. Accents and punctuation are stripped, dates accept YYYY-MM-DD or DD-MM-YYYY. Everything is computed locally and deterministically, so it is instant and private. Ideal for astrology and self-discovery apps, dating and personality products, content and entertainment sites, and novelty widgets. For entertainment and self-reflection. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is numerology; for sun-sign zodiac use a zodiac API and for tarot draws use a tarot API.

Uptime

100.0%

Latency

80ms

Subs

4,072

Aquarium maths as an API, computed locally and deterministically. The volume endpoint computes a tank's water volume — in US and UK gallons and litres — for a rectangular, cube, cylinder, hexagonal or bow-front tank from its dimensions (inches by default, or centimetres, millimetres and metres), and applies a fill factor (default 0.9) for substrate, decoration and freeboard to give a realistic net volume. The stocking endpoint gives a rough stocking load from the tank volume and the total length of fish using the classic inch-per-gallon guideline, reporting the maximum recommended inches and how heavily stocked the tank is. The waterchange endpoint computes the water-change volume for a percentage, with an optional dechlorinator dose. Everything is computed locally and deterministically, so it is instant and private. Stocking is a rough beginner guideline only — real stocking depends on the species, filtration and bioload. Ideal for aquarium and fishkeeping apps, pet-shop and hobbyist tools, and tank-setup planners. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is aquarium maths; for swimming-pool volume and chemical dosing use a pool API and for storage-tank gauging use a tank API.

Uptime

100.0%

Latency

76ms

Subs

4,856

Ideal-gas-law maths as an API, computed locally and deterministically. The ideal endpoint solves PV = nRT for whichever quantity you leave out: provide any three of pressure, volume, amount of substance (moles) and temperature, and it returns the fourth in several units. The combined endpoint applies the combined gas law, P₁V₁/T₁ = P₂V₂/T₂: give a first state and two quantities of the second state and it finds the missing one — handy for "what happens to the volume if I double the pressure" questions. The density endpoint computes the density of an ideal gas from the pressure, temperature and molar mass (ρ = P·M / R·T). Pressure accepts pascals, kPa, bar, atm, psi, mmHg and Torr; volume accepts m³, litres, mL and cubic feet; temperature accepts kelvin, Celsius and Fahrenheit; and the gas constant R is 8.314462618 J/(mol·K). Everything is computed in SI internally and is instant and private. Ideal for chemistry and physics education, lab and process tools, HVAC and scuba calculations, and engineering software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is ideal-gas thermodynamics; for the chemical elements and periodic-table data use an elements API.

Uptime

100.0%

Latency

78ms

Subs

4,439

Paper-weight maths as an API, computed locally and deterministically. The convert endpoint converts between grammage (GSM, grams per square metre — the universal measure) and the US basis weight in pounds, which depends on the paper stock type: bond/writing (basis 17×22 in), text/book/offset (25×38), cover (20×26), index (25.5×30.5), tag (24×36) and bristol (22.5×28.5). The weight endpoint computes the mass of a single sheet, a 500-sheet ream and the M-weight (the weight of 1000 sheets in pounds) at a given grammage and sheet size — accepting dimensions in millimetres, centimetres, inches or metres, or a named size (A3–A5, letter, legal, tabloid). The stocks endpoint is a reference of the US stock types with their conversion factors and basis sizes. Everything is computed locally and deterministically, so it is instant and private. Ideal for printing and publishing tools, stationery and packaging apps, print-shop estimators, and shipping-weight calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is paper grammage and basis weight; for general mass-unit conversion use a unit-conversion API.

Uptime

100.0%

Latency

74ms

Subs

4,335

Fertilizer maths as an API, computed locally and deterministically. The rate endpoint works out how much fertilizer product to apply to hit a target nitrogen rate over an area: from the N-P-K analysis (such as 10-10-10 or 20-5-10), a target pounds of nitrogen per 1000 ft² (or per 100 m²) and the area, it returns the product weight and the pounds of nitrogen, phosphate and potash applied. The nutrients endpoint reports the pounds of nitrogen, P₂O₅ and K₂O — and the elemental phosphorus and potassium — in a bag of a given weight and analysis. The coverage endpoint works out how much area a bag covers at a target nitrogen rate. N-P-K are percent by weight; phosphorus is reported as P₂O₅ and potassium as K₂O following the label convention, with the elemental amounts alongside (P₂O₅ × 0.4364, K₂O × 0.8301). Everything is computed locally and deterministically, so it is instant and private. Ideal for lawn-care and gardening apps, agriculture and turf tools, and landscaping and quoting software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is fertilizer rate maths; for mulch, gravel and topsoil quantities use a landscaping API.

Uptime

100.0%

Latency

73ms

Subs

4,512

Slope and grade maths as an API, computed locally and deterministically. The convert endpoint converts a slope between every common form — percent grade, angle in degrees, a ratio such as 1:12, per mille and rise-per-run — where the slope m = rise ÷ run = tan(angle). The distance endpoint relates the run (horizontal), the rise (vertical) and the slope distance (the hypotenuse) of a right-triangle slope: give any two, optionally with the grade or angle, and it returns the rest. The ramp endpoint sizes a wheelchair or ADA ramp — from a rise and a maximum slope (defaulting to 1:12, the ADA maximum of 8.33%) it returns the required run and total ramp length, and if you supply an actual run it checks whether the ramp is within the limit. Everything is computed locally and deterministically, so it is instant and private. Ideal for civil-engineering and surveying tools, road, trail and accessibility apps, construction and ramp design, and mapping software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is slope and grade geometry; for roof pitch specifically use a roofing API.

Uptime

100.0%

Latency

77ms

Subs

3,042

Water-hardness maths as an API, computed locally and deterministically. The convert endpoint converts a hardness value between all the common units — parts per million / milligrams per litre as calcium carbonate, grains per US gallon, German degrees (°dH), French degrees (°f), English or Clark degrees, and millimoles per litre — passing everything through ppm (1 gpg = 17.118 ppm, 1 °dH = 17.848, 1 °f = 10, 1 °Clark = 14.254), and classifies the result. The classify endpoint labels a value as soft, moderately hard, hard or very hard on the USGS/WHO scale. The softener endpoint sizes a water softener: from the hardness and the household water use it works out the grains of hardness removed per day and the grain capacity needed between regenerations. Everything is computed locally and deterministically, so it is instant and private. Ideal for water-treatment and plumbing tools, aquarium and pool apps, appliance and softener sizing, and home and lab software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is water-hardness conversion; for general unit conversion use a unit-conversion API and for swimming-pool dosing use a pool API.

Uptime

100.0%

Latency

81ms

Subs

3,880