---
title: "Pythagorean Theorem Calculator — a² + b² = c²"
description: "Calculate any side of a right triangle using the Pythagorean theorem. Find hypotenuse or either leg. Shows Pythagorean triples and triangle area. Free."
url: "https://worldcalculators.org/calculators/pythagorean-theorem/"
canonical: "https://worldcalculators.org/calculators/pythagorean-theorem/"
---

# Pythagorean Theorem Calculator

Calculate any side of a right triangle using the Pythagorean theorem. Find hypotenuse or either leg. Shows Pythagorean triples and triangle area. Free.

## Quick answer

a² + b² = c² where c is the hypotenuse (longest side). To find c: c = √(a² + b²). To find a: a = √(c² − b²). The famous 3-4-5 triple: 3² + 4² = 9 + 16 = 25 = 5².

## Frequently Asked Questions

In any right triangle: a² + b² = c², where c is the hypotenuse (the side opposite the right angle). It works for any consistent unit — mm, cm, m, ft, in.
(3,4,5), (5,12,13), (8,15,17), (7,24,25), (20,21,29). Any multiple works: (6,8,10), (9,12,15). These are used in construction to verify right angles.

Source: https://worldcalculators.org/calculators/pythagorean-theorem/
Markdown mirror of the HTML page. Prefer this URL for RAG; the interactive calculator still lives on the HTML page.