Pythagorean Theorem Calculator
Enter any two sides of a right triangle to find the missing one.
Solve any right triangle
The Pythagorean theorem, a² + b² = c², links the three sides of every right triangle. Give this calculator any two sides and it solves for the third, whether that is the hypotenuse or one of the legs.
With legs of 3 and 4 the hypotenuse is exactly 5 — the classic 3-4-5 triangle. Leave the hypotenuse blank to find it, or fill it in and leave a leg blank to solve the other way.
Accurate and private
When solving for a leg it checks that the hypotenuse really is the longest side, so impossible triangles are flagged rather than returning a wrong answer. The math runs in your browser.
Frequently Asked Questions
What does the calculator solve?
Any missing side of a right triangle. Leave one field blank (or zero) and it solves for it using a² + b² = c², where c is the hypotenuse.
Which side is the hypotenuse?
The longest side, opposite the right angle. It must be larger than either leg, and the tool checks that when you solve for a leg.
Can I use it for distance?
Yes — the straight-line distance between two points is a Pythagorean calculation on the horizontal and vertical gaps.
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