Pythagorean Theorem Calculator

For a right triangle, the square of the hypotenuse (the side opposite the right angle) equals the sum of the squares of the other two sides: a² + b² = c². This calculator uses that relationship to find a missing side.

Choose "Hypotenuse (from two legs)", then enter the two shorter sides (the legs). The calculator returns c = √(a² + b²), along with the triangle's area, perimeter, and acute angles.

Choose "A leg (from hypotenuse + leg)", enter the hypotenuse and the leg you know, and the calculator returns the other leg as √(c² − a²). The known leg must be shorter than the hypotenuse, otherwise no real triangle exists.

No. Everything is computed in your browser with JavaScript. The values you enter stay on this page and are never uploaded to a server.