Pythagorean Theorem Calculator

Calculate the hypotenuse of a right triangle from the lengths of its legs.

01 / INPUTS

Leg A

units

Leg B

units

02 / RESULT

HYPOTENUSE

5 units

Hypotenuse: 5 units

Calculation trace

√(3² + 4²) = 5
5 units
Hypotenuse

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How it works

For a right triangle the hypotenuse is c = √(a² + b²), where a and b are the two legs.

Assumptions & limits

Applies to right triangles only.
Both legs must be positive lengths.

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FAQ

Can I find a leg instead of the hypotenuse?: This tool computes the hypotenuse from two legs. To find a leg, rearrange as a = √(c² − b²).

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Related calculators

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SOURCES

OpenStax, Rice University
Prealgebra 2e ↗
Pythagorean theorem: the hypotenuse c = √(a² + b²) of a right triangle
Accessed 2026-08-23