Developer API

PrimeCalcPro Calculator API

Integrate PrimeCalcPro professional calculators into your applications. Access 4,600+ finance, math, and science tools via a simple REST API.

Get API Key →View pricing OpenAPI spec

Try it live

Pick a calculator, enter your API key and inputs, and see a live response.

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Authentication

All API requests require an API key sent via the X-API-Key header. Manage your keys in the API dashboard →

curl -X POST https://www.primecalcpro.com/api/v1/calculate \
  -H "Content-Type: application/json" \
  -H "X-API-Key: YOUR_API_KEY" \
  -d '{"calculator": "percentage", "inputs": {"value": 200, "percentage": 15}}'

Calculate Endpoint

POST/api/v1/calculate

Request body

{
  "calculator": "compound-interest",
  "inputs": {
    "principal": 1000,
    "rate": 5,
    "years": 10,
    "compounding": "annually"
  }
}

Response

{
  "success": true,
  "calculator": "compound-interest",
  "result": {
    "results": {
      "futureValue": { "value": 1628.89, "label": "Future Value", "unit": "$" },
      "totalInterest": { "value": 628.89, "label": "Total Interest", "unit": "$" }
    },
    "explanation": "With $1,000 at 5% compounded annually for 10 years, the investment grows to $1,628.89."
  },
  "cached": false,
  "timestamp": "2026-05-14T10:30:00.000Z"
}

API Reference

GET/api/v1/calculators

List all available calculators. No API key required. Supports ?category=math and ?q=bmi query filters. Returns { total, calculators: [{ slug, title, description, category, subcategory, hasFormula }] }.

GET/api/v1/calculators/:slug

Get full schema/info for a specific calculator, including formula and usage instructions. No API key required. Returns 404 if the slug is unknown.

POST/api/v1/calculate

Runs a calculation. Requires X-API-Key. Body: { calculator: string, inputs: object }. Responses are cached for 10 minutes per unique input combination.

Code Examples

curl -X POST https://www.primecalcpro.com/api/v1/calculate \
  -H "Content-Type: application/json" \
  -H "X-API-Key: YOUR_API_KEY" \
  -d '{"calculator": "bmi", "inputs": {"weight": 70, "height": 175, "unit": "metric"}}'

Rate Limits

Plan	Requests / Day	API Keys
Hobby (Free)	100	1
Developer	10,000	3
Business	100,000	10
Enterprise	Unlimited	50

See the full API pricing page for plan details.

Error Codes

Code	Meaning
401	Missing or invalid API key
403	API key revoked
404	Calculator not found
429	Rate limit exceeded

Ready to integrate?

Create an API key from the dashboard and start building with professional-grade calculators.

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