Hypotenuse Calculator

About this calculator

The Pythagorean theorem states that in 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, so c = √(a² + b²). It's one of the oldest and most widely proven theorems in mathematics, with recorded proofs dating back to ancient Babylon, Egypt, and Greece.

Beyond the classroom, it's a daily working tool: carpenters and builders use it to check that corners are square (the “3-4-5 rule”), calculate diagonal bracing and staircase stringers; surveyors and engineers use it for distance and elevation calculations; and it underlies distance formulas in navigation, computer graphics, and physics. Enter the two legs (or a leg and the hypotenuse) to solve the triangle.