Find the hypotenuse — or any missing side — of a right triangle instantly.
What do you want to find?
Enter Both Legs
c = √(a² + b²)
Result
About the Pythagorean Theorem
Use this hypotenuse calculator to instantly apply the Pythagorean theorem (a² + b² = c²) to any right triangle. Enter both legs to find the hypotenuse, or provide the hypotenuse and one leg to solve for the missing side. Each calculation also returns the triangle's area, perimeter, and the two non-right angles — no manual arithmetic needed.
The hypotenuse is the longest side of a right triangle — the side directly opposite the 90° angle. Its length equals the square root of the sum of the squares of the other two sides: c = √(a² + b²).
Rearrange the Pythagorean theorem: a = √(c² − b²). Enter the hypotenuse and the known leg into the 'Find Missing Leg' mode and the calculator solves it instantly.
Pythagorean triples are sets of three positive integers that satisfy a² + b² = c² exactly. Common examples include (3, 4, 5), (5, 12, 13), (8, 15, 17), and (7, 24, 25). They appear frequently in geometry and construction.
Yes. You can enter any positive decimal number for the legs or hypotenuse. The result is computed with full floating-point precision and displayed to six significant figures.