FinCalculator
Taxation & Salary APIWeb Calculator UI

Free Old Tax Regime Calculator API (2026)

API calculating income tax under Old Tax Regime.

Interactive API Playground & Live Test

GET/api/v1/income-tax

Query Parameters

Gross annual income in ₹, after 80C, 80D and other deductions; the ₹50,000 standard deduction is subtracted for you

old (the route defaults to new, so pass it)

curl -X GET "https://fincalculator.in/api/v1/income-tax?income=1500000&regime=old" \
  -H "Accept: application/json"
Live JSON Response (HTTP 200 OK)
Click "Execute Live API Request" below...

Request Parameters Schema

ParameterTypeRequiredDescription / Notes
incomenumberRequiredGross annual income in ₹, after 80C, 80D and other deductions; the ₹50,000 standard deduction is subtracted for you
regimestringRequiredold (the route defaults to new, so pass it)

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Frequently Asked Questions (FAQs)

Is the Free Old Tax Regime Calculator API free to use in production apps?
Yes! All FinCalculator REST APIs are completely free, zero-auth, open-CORS, and edge-cached for high performance across global web and mobile applications.
What is the rate limit for /api/v1/income-tax?
Endpoints are cached at the edge for 24 hours. There are no restrictive rate limits for standard web traffic and mobile applications.