Business & SME APIWeb Calculator UI

Free GST Amount & Rate Calculator API (2026)

GST calculation API for inclusive and exclusive price calculations.

Interactive API Playground & Live Test

GET/api/v1/gst

Zero Auth • Open CORS

Query Parameters

amountnumber • required

Base amount in ₹

ratenumber • required

GST rate % (5, 18, 40)

inclusiveboolean • optional

Set "true" if amount includes GST

curl -X GET "https://fincalculator.in/api/v1/gst?amount=10000&rate=18&inclusive=false" \
  -H "Accept: application/json"

Live JSON Response (HTTP 200 OK)

Click "Execute Live API Request" below...

Request Parameters Schema

Parameter	Type	Required	Description / Notes
amount	number	Required	Base amount in ₹
rate	number	Required	GST rate % (5, 18, 40)
inclusive	boolean	Optional	Set "true" if amount includes GST

Related Business & SME APIs

GET /api/v1/gst-itcFree GST Input Tax Credit (ITC) Calculator API GET /api/v1/startup-burn-rateFree Startup Burn Rate & Cash Runway API GET /api/v1/rental-yieldFree Rental Yield & Property Income API GET /api/v1/net-worthFree Net Worth Tracker & Debt-to-Asset API

Frequently Asked Questions (FAQs)

Is the Free GST Amount & Rate 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/gst?

Endpoints are cached at the edge for 24 hours. There are no restrictive rate limits for standard web traffic and mobile applications.