API · /percentage-api

Percentage API

healthy 3,723 Subscribers

Everyday percentage maths as an API. Four clear operations: what is X% of a value (15% of 200 = 30); what percentage one number is of another (30 is 15% of 200); the percentage change between two numbers, with the direction and the raw difference (200 → 250 is a 25% increase); and applying a percentage increase or decrease to a value (200 + 15% = 230). Handy for discounts, tips and tax, growth and KPI deltas, progress bars, dashboards and quick spreadsheet-style sums — without writing a formula. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 5 endpoints. A focused calculator, distinct from a general math-expression engine.

#percentage #calculator #math #finance #utilities #developer-tools

api.oanor.com/percentage-api

Get an API key Try in playground → Contact provider

Machine-readable spec so AI agents can integrate this API.

/api/percentage-api/openapi.json

/api/percentage-api/llms.txt

Discovery: GET /api/index.json lists every API.

Percentage API — live data on the oanor API marketplace

API health

healthy

Uptime: 100.00%; Server probes · 24h
Avg latency: 74 ms; Server probes · 24h
Subscribers: 3,723; active
Total calls: 95; last 7 days

Full status page → · 15 probes/24h

Pricing

Pick a tier — billed monthly, cancel anytime.

Free

1,095 calls / month
2 requests / second
Hard cap (429 above quota, no overage)
1,095 calls/month
2 req/sec
Of + what + change + apply
No credit card

Starter

€1.35 /month

9,350 calls / month
8 requests / second
Hard cap (429 above quota, no overage)
9.35k calls/month
8 req/sec
All four operations
Email support

Pro

€21.25 /month

144,500 calls / month
20 requests / second
Hard cap (429 above quota, no overage)
144.5k calls/month
20 req/sec
Dashboard / finance pipelines
Priority support

Mega

€59.25 /month

765,000 calls / month
50 requests / second
Hard cap (429 above quota, no overage)
765k calls/month
50 req/sec
Platform scale
Dedicated SLA

Built by

PremiumApi

Related APIs

Other APIs with overlapping tags.

Dollar-Cost Averaging API

Live dollar-cost-averaging analytics that investors run to see how periodic buying plays out — computed on demand from the price series you pass in, no key, nothing cached. Get the outcome of investing a fixed amount each period (total invested, units accumulated, average cost, current value, profit and ROI) with a lump-sum comparison; the per-period breakdown; and a ranking of dollar-cost averaging against lump-sum, best-case and worst-case timing. Works for any market — stocks, crypto, ETFs or forex. A dollar-cost-averaging engine, distinct from compound-interest and return-analysis tools: it turns a price path and a contribution into the cost basis and outcome of buying over time.

api.oanor.com/dca-api

Forex Calculator API

Live foreign-exchange trading calculators computed from live ECB reference rates. The pip-value endpoint returns what one pip of a currency pair is worth, in the trader's account currency, for a given lot size. The position-size endpoint returns how many lots to trade to risk a fixed percentage of the account on a given stop-loss. The profit-loss endpoint returns the P&L of a trade from its entry, exit and direction. The margin endpoint returns the margin a position requires at a given leverage. All conversion to the account currency uses live exchange rates. Computed live, nothing stored. Distinct from raw FX-rate feeds — this turns rates into the pip values, position sizes, margins and P&L a trader acts on.

api.oanor.com/fxcalculator-api

Tip Calculator API

Work out tips and split a bill — with exact cent maths so the per-person amounts always add back up to the total, no penny ever lost to rounding. The calc endpoint takes a bill, a tip percentage (15% by default) and a number of people and returns the tip amount, the grand total, the per-person amount, the effective tip percentage, and — when you want a tidy number — an optional rounding of the total either up to the next whole unit or to the nearest. When the bill does not divide evenly it produces a fair share list where a few people pay one cent more, so the parts sum precisely. The split endpoint divides any amount, optionally adding a tip first, evenly among people and returns that exact per-person share list. Everything is computed in integer cents locally and deterministically, so it is instant, private and always balances. Currency-agnostic — the numbers work for any currency. Ideal for restaurant and POS apps, expense-sharing and group-payment tools, delivery and service apps, and everyday bill splitting. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This calculates tips and splits; for percentage maths in general use a percentage API and for invoicing margins use a margin API.

api.oanor.com/tip-api

GPA API

Calculate a weighted grade-point average (GPA). The calc endpoint takes a list of courses — each with a grade and the credit hours it is worth — and returns the credit-weighted GPA, the totals, and a per-course breakdown of quality points so you can see exactly how the average was formed. Grades may be US letter grades (A, A-, B+, … F) on the standard 4.0 scale, or 4.3 with the us_plus scale that gives A+ extra weight; percentages from 0 to 100 mapped to letters and points with the usual cutoffs; raw grade points given directly as numbers; or your own custom letter-to-point mapping for any institution's scheme. Courses can be passed as a JSON array or a compact string like "A:3,B+:4,C:2", and credits default to 1 for an unweighted average. The scales endpoint lists the built-in grade scales and their point values. Everything is computed locally and deterministically, so it is instant and private — no student data is stored. Ideal for student planners and dashboards, university and school portals, LMS and ed-tech apps, scholarship and admissions tools, and academic what-if calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This computes GPA; for general statistics use a statistics API.

api.oanor.com/gpa-api

Frequently asked questions

Quick answers about pricing, quotas, and integration.

How do I get an API key for Percentage API?

Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Percentage API with the x-oanor-key header. No credit card needed for the free tier.

What's the rate limit for Percentage API?

Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.

How much does Percentage API cost?

Percentage API has a free tier with 100 calls / month. Paid plans start at €1.35 / month with higher quotas and faster rate limits.

Can I cancel my subscription anytime?

Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.

Is Percentage API GDPR-compliant?

All requests to Percentage API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.

Custom headers

Language: Client:

Code snippets

curl https://api.oanor.com/percentage-api/SOME_PATH \
  -H "x-oanor-key: oanor_test_..."

const res = await fetch("https://api.oanor.com/percentage-api/SOME_PATH", {
  headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();

$ch = curl_init("https://api.oanor.com/percentage-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);

import requests
r = requests.get(
    "https://api.oanor.com/percentage-api/SOME_PATH",
    headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())

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Percentage API

API health

Pricing

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Related APIs

Dollar-Cost Averaging API

Forex Calculator API

Tip Calculator API

GPA API

Frequently asked questions

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