Percentage Calculator API: The Complete Guide

Need to calculate percentages in your application? This guide covers everything you need to know about percentage calculations via API, including percentage of values, percentage change, and implementation examples in multiple languages.

What is a Percentage?

A percentage is a number expressed as a fraction of 100, represented by the symbol %. Percentages are used everywhere in daily life, from discounts and taxes to statistics and data analysis. Programmatic percentage calculations are essential for e-commerce, finance, and analytics applications.

For example, 25% of 200 is calculated as: (25/100) * 200 = 50

Types of Percentage Calculations

The API supports multiple percentage calculation types:

Percentage of a Value

Calculate what X% of a number is. For example, what is 15% of 500? Answer: 75.

Percentage Change

Calculate the percentage increase or decrease between two values. Essential for tracking growth, performance metrics, and financial analysis.

What Percentage

Determine what percentage one number is of another. For example, 25 is what percent of 200? Answer: 12.5%.

Using the Percentage Calculator API

TinyFn provides a simple endpoint to calculate percentages:

GET https://api.tinyfn.io/v1/math/percentage
Headers: X-API-Key: your-api-key

{
  "result": 75,
  "calculation": "15% of 500",
  "formula": "(15/100) * 500"
}

Parameters

Code Examples

JavaScript / Node.js

const response = await fetch(
  'https://api.tinyfn.io/v1/math/percentage?type=of&percentage=15&value=500',
  { headers: { 'X-API-Key': 'your-api-key' } }
);
const { result } = await response.json();
console.log(result); // 75

Python

import requests

response = requests.get(
    'https://api.tinyfn.io/v1/math/percentage',
    params={'type': 'of', 'percentage': 15, 'value': 500},
    headers={'X-API-Key': 'your-api-key'}
)
result = response.json()['result']
print(result)  # 75

cURL

curl "https://api.tinyfn.io/v1/math/percentage?type=of&percentage=15&value=500" \
  -H "X-API-Key: your-api-key"

Common Use Cases

• E-commerce Discounts: Calculate discount amounts and final prices
• Financial Analysis: Track percentage changes in stocks, revenue, or metrics
• Tax Calculations: Compute tax amounts based on percentage rates
• Grade Calculations: Convert scores to percentages for educational apps
• Analytics Dashboards: Display percentage changes in KPIs and metrics

Best Practices

1. Handle precision: Use appropriate decimal places for financial calculations
2. Validate inputs: Ensure percentage values are within expected ranges
3. Consider rounding: Define rounding rules for consistent results
4. Cache results: Cache frequently used calculations to improve performance