🔌 Free Calculator API

Iwwersiicht

D'API féiert déi selwecht Mathematik aus wéi d'Websäit. Setzt Feldwäerter vun engem Rechner als Ufroparameter oder JSON an kritt d'berechent Resultater als JSON zréck - inklusiv all Amortisatiounsplang oder Diagrammdaten déi de Rechner produzéiert.

• 198+ Rechner, all mat engem eegenen Endpunkt
• Keng API Schlëssel — anonymous access, rate-limited by IP
• CORS — Access-Control-Allow-Origin: * (Clientsäit)
• Rate Limit: 60 Ufroen/Stonn pro IP (HTTP 429 wann iwwerschratt)
• Errors are free — only a successful (2xx) response uses one call from your monthly quota. Every 400, 401, 404, 429 and 500 costs you nothing.

Basis- URL

https://calculator.free/api/v1/

Index — all Rechner opzielen

GET https://calculator.free/api/v1/

D'Resultat ass eng ganz Rei vu verschiddene Formen, déi all op eng aner Manéier funktionnéieren (z. B. d'Resultat vun enger Geschicht, engem Film, enger Serie, enger Serie vu Lidder, asw.). Each field also carries a required flag — true for the few fields that have no default (dates, mostly). Send those: a couple of calculators can infer one, the rest answer 400 without it.

Rechen - e Rechner ausféieren

GET  https://calculator.free/api/v1/<slug>/?field=value&field=value
POST https://calculator.free/api/v1/<slug>/     (JSON or form body)

Antwortform:

{
  "ok": true,
  "slug": "mortgage",
  "country": "us",
  "inputs":   { ... the values actually computed with ... },
  "results":  { ... computed result keys ... },
  "schedule": { "columns": [...], "rows": [...] } | null,
  "chart":    { "type": "pie", "slices": [...] } | null,
  "defaults_applied": ["tax", "insurance"]
}

D'Sozialversécherung (Sozialversécherung, Sozialversécherung, Sozialversécherung, Sozialversécherung) ass eng staatlech Gesondheets- a Fleegeversécherung. ?country=us|uk|ca|au|in|ie|nz|za. D'Grenz tëscht dem Land an der Belsch ass net ganz kloer, well et 400 Kilometer Grenz tëscht dem Land an der Belsch gëtt.

Parameters, defaults and errors

Send only the fields you care about. Anything you leave out is filled with that field's published default — the same value the calculator page pre-fills, so the API and the website always return the same numbers for the same inputs. Each response lists what it filled in under defaults_applied.

Anything the API cannot resolve honestly is an error, never a zero: a misspelled parameter, a value of the wrong type, an unknown dropdown option, or a missing field that has no default (the date fields — a birth date cannot be guessed). Every 400 names the offending parameter and echoes the full field spec so a client can correct itself.

$ curl "https://calculator.free/api/v1/mortgage/?price=350000&rate=6.5&term=30"
{
  "ok": false,
  "error": "unknown_parameter",
  "message": "Unknown parameter 'term' for calculator 'mortgage'. Did you mean 'years'? ...",
  "unknown_parameters": ["term"],
  "did_you_mean": { "term": "years" },
  "valid_parameters": ["down", "extra", "extra_onetime", "extra_yearly", "hoa",
                       "insurance", "other", "pmi", "price", "rate", "tax", "years"],
  "fields": [ ... ]
}

The /api/v1/ index publishes every field's key, type, unit, default and whether it is required — enough to build a client that never guesses.

Authentifizéierung

Dir kënnt d'API ouni Schlëssel opruffen - anonym Ufroe sinn duerch IP limitéiert. Fir eng méi héich, virsiichteg monatlech Quota (an kommerziell Benotzung), erstellen en Schlëssel op Ärer Kontsäit an schécken et op eng vun den dräi Manéiere:

GET  https://calculator.free/api/v1/mortgage/?price=350000&key=YOUR_KEY
curl -H "Authorization: Bearer YOUR_KEY" "https://calculator.free/api/v1/bmi/?units=metric&height=180&weight=80"
curl -H "X-Api-Key: YOUR_KEY"           "https://calculator.free/api/v1/bmi/?units=metric&height=180&weight=80"

• Free — anonym (IP-Rate-limitéiert) oder e gratis Schlëssel mat enger klenge monatlecher Quot. Net kommerziell.
• Entwéckler — $9/mo — 10.000 Leit, déi am 1.
• Business — $49/mo — 100.000 Leit, déi d'Spill spillen.

What counts against your quota

Only a successful response does. One 2xx = one call. Every error is free: a 400 for a misspelled parameter, a bad value or a missing required field, a 404 for an unknown slug, a 401 for a bad key, a 429, and anything that goes wrong on our side. Explore the contract and fix your request as many times as you need — you are billed for answers, not for corrections.

Because errors are free they are rate-limited instead: if one key provokes more than 200 rejected responses in an hour, it gets HTTP 429 "too_many_invalid_requests" until the hour rolls over. Successful calls never count towards that, so a working integration will never see it — it only catches a client stuck in a retry loop.

Wann d'Spill op engem Computer gespillt gëtt, gëtt et eng 4000-Spill-Optioun, déi op der 4000-Spill-Säit verfügbar ass. Si ass och an der Lëscht vun de gréisste Stären opgeholl. Präis Säit.

Beispiller

curl

curl "https://calculator.free/api/v1/mortgage/?price=350000&down=70000&rate=6.9&years=30"

JavaScript fetch()

const r = await fetch(
  "https://calculator.free/api/v1/bmi/?" + new URLSearchParams({
    units: "metric", height: "180", weight: "80"
  }));
const { results } = await r.json();
console.log(results.bmi, results.category);

Python

import requests

r = requests.get("https://calculator.free/api/v1/mortgage/",
                 params={"price": 350000, "down": 70000,
                         "rate": 6.9, "years": 30},
                 headers={"Authorization": "Bearer YOUR_KEY"})
print(r.json()["results"])

POST JSON

curl -X POST "https://calculator.free/api/v1/income-tax/?country=uk" \
  -H "Content-Type: application/json" \
  -d '{"income": 60000}'

All Endpunkten

E Endpunkt pro Rechner. Feldschlëssel an Resultatschlëssel fir all sinn am /api/v1/ Index.