Pythagorean Theorem Calculator

About this calculator

The Pythagorean theorem says that in a right triangle, the square of the hypotenuse equals the sum of the squares of the two legs: c² = a² + b². Enter the legs and the hypotenuse is the square root of that sum — the classic 3-4-5 triangle gives √(9 + 16) = 5.

To find a missing leg instead, rearrange: a = √(c² − b²). Enter the hypotenuse as one "leg" here and take the result with the larger value as c — or simply check that the numbers satisfy a² + b² = c².

The theorem only holds for right triangles, but it hides everywhere: diagonal of a TV screen, the shortest path across a rectangular field, distance between two points on a map.