#wellness

Sauna-heater sizing maths as an API, computed locally and deterministically — the heater-power, stone-mass and electrical numbers a sauna builder, installer or wellness retailer sizes a cabin with. The heater-size endpoint gives the power: about 1 kW per 1.3 m³ of well-insulated cabin (room volume ÷ 1.3), with cold surfaces the heater must also warm — a glass door or wall, bare stone, tile or uninsulated timber — adding roughly 1.2 m³ of equivalent volume per square metre, so a 10 m³ room with a 2 m² glass door wants about a 10 kW heater, rounded up to the next standard size. The stones endpoint gives the recommended sauna-stone mass, roughly 10–20 kg per kW (more stones for a softer, steamier löyly, fewer for a faster warm-up), with a note to use proper peridotite/olivine stones stacked loosely. The electrical endpoint gives the current the resistive heater draws — power ÷ voltage for single-phase or ÷ (√3 × voltage) for three-phase, since most heaters above ~4 kW are wired three-phase to keep the per-leg current and cable size down — to size the breaker and the dedicated RCD-protected circuit. Everything is computed locally and deterministically, so it is instant and private. Ideal for sauna and wellness retailers, home-improvement and DIY tools, and HVAC/electrical estimating apps. Pure local computation — no key, no third-party service, instant. Estimates — follow the heater maker's chart and local wiring code. 3 compute endpoints. For steam-boiler maths use a boiler API; for room heat loss a U-value API.

api.oanor.com/saunaheater-api

Body-fat-percentage and body-composition maths as an API, computed locally and deterministically. The navy endpoint applies the US Navy circumference method — for men %BF = 495/(1.0324 − 0.19077·log10(waist − neck) + 0.15456·log10(height)) − 450, and for women a formula that adds the hip measurement — to estimate body fat from a tape measure alone, returning the percentage and the fitness category (essential, athletes, fitness, acceptable or obese); a man of 178 cm with a 40 cm neck and 90 cm waist reads about 18.7 %. The deurenberg endpoint gives the BMI-based estimate %BF = 1.20·BMI + 0.23·age − 10.8·(1 if male) − 5.4 from BMI or weight and height plus age. The composition endpoint splits a total weight into fat mass and lean (fat-free) mass from a body-fat percentage. Circumferences and height are in centimetres and weight in kilograms. Everything is computed locally and deterministically, so it is instant and private. Ideal for fitness, wellness, gym, nutrition, body-tracking and health-education app developers, body-composition and progress-tracking tools, and coaching software. These are estimation formulas, not a substitute for DEXA or professional assessment. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is body-fat percentage; for body-mass index use a BMI API and for basal metabolic rate a BMR API.

api.oanor.com/bodyfat-api