Skip to content
Calculator Tools
Geometry Calculators

Pythagorean Theorem Calculator

Find the missing side of a right triangle with a² + b² = c² — solve for the hypotenuse or either leg.

Enter values

Results update as you type.

Result

Hypotenuse c

5

Step-by-stepShow
  1. c = √(3² + 4²) = 5

About the Pythagorean Theorem Calculator

Find the missing side of a right triangle with a² + b² = c² — solve for the hypotenuse or either leg.

Also known as: pythagoras calculator, hypotenuse calculator, a2 + b2 = c2, right triangle side, find the hypotenuse.

How to use this calculator

  1. Enter solve for.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Open “Step-by-step” to see how the answer was worked out.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

a² + b² = c²

Worked example

Using the values pre-filled in the calculator above:

  • Solve for: Hypotenuse c
  • Leg a = 3
  • Leg b = 4

the calculator returns:

  • Hypotenuse c: 5

Working

  1. c = √(3² + 4²) = 5

Frequently asked questions

Does the Pythagorean theorem work for any triangle?

Only for right triangles. For other triangles use the law of cosines, which reduces to Pythagoras when the angle is 90°.