Calcimator API

Access 5,000+ calculator engines via REST API. Build powerful calculation features into your apps, websites, and services.

Get API Key Try Playground OpenAPI Spec

5,000+ Endpoints

Every calculator is an API endpoint. Financial, health, math, engineering — all accessible programmatically.

Simple Auth

Pass your API key in the X-API-Key header. No OAuth, no tokens, no complexity.

Real-time Usage

Track your API usage in real-time from your dashboard. Monitor requests, errors, and top calculators used.

Quick Start

1. Get your API key

Create an API key from your dashboard.

2. Make a request

curl -X POST https://calcimator.com/api/v1/calculators/tip/calculate \
  -H "Content-Type: application/json" \
  -H "X-API-Key: YOUR_API_KEY" \
  -d '{"inputs": {"billAmount": 85, "tipPercentage": 18}}'

3. Get results

{
  "values": {
    "tipAmount": 15.3,
    "totalAmount": 100.3,
    "tipPerPerson": 15.3,
    "totalPerPerson": 100.3
  }
}

JavaScript Example

const response = await fetch(
  "https://calcimator.com/api/v1/calculators/mortgage/calculate",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "X-API-Key": process.env.CALCIMATOR_API_KEY,
    },
    body: JSON.stringify({
      inputs: {
        loanAmount: 300000,
        interestRate: 6.5,
        loanTerm: 30,
      },
    }),
  }
);

const { values } = await response.json();
console.log("Monthly payment:", values.monthlyPayment);

Rate Limits

Tier	Requests/Day	Price
Free	100	$0
Pro	10,000	$4.99/mo
Business	100,000	$14.99/mo