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Tools.Town
Free Online Tools for Everyone

Percentage Calculator API

Calculate X% of a number, find what percent X is of Y, or compute percentage change — instantly.

Category: Calculators Endpoint: /v1/calculators/percentage Method: GET Auth: API Key

Fast & Accurate

Get precise results instantly.

Easy Integration

Simple REST API with JSON response.

Developer Friendly

Clear docs and SDK examples.

Free to Start

1,000 free requests/month.

Endpoint

All requests should be made to the following endpoint:

GET https://api.tools.town/v1/calculators/percentage

Authentication

This endpoint requires an API Key. Include your API key in the request header.

Authorization: Bearer YOUR_API_KEY
You can get your API key from your dashboard.

Request Parameters

Send a GET request with query parameters.

Parameter Type Required Description Example
mode string Calculation mode: find, what-percent, or change. find
percent number Percentage value. 15
of number Base number. 2000

Example Request

curl -G "https://api.tools.town/v1/calculators/percentage" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  --data-urlencode "mode=find" \
  --data-urlencode "percent=15" \
  --data-urlencode "of=2000"

Error Codes

Code Meaning
400 Bad Request — missing or invalid parameter
401 Unauthorized — API key missing or invalid
429 Rate limit exceeded — free tier: 1,000 requests/month
500 Internal Server Error — try again or contact support