Pythagorean Theorem Calculator

Solve for a missing side of a right triangle.

Pythagorean Theorem Calculator helps you solve for a missing side of a right triangle. Enter a, b, and c, review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the Pythagorean Theorem calculator does Pythagorean Theorem Calculator is built for arithmetic, algebra, geometry, and number tools. Solve for a missing side of a right triangle. You enter a, b, and c, then Simple Calculators computes the result instantly. Results use standard school and engineering formulas that run privately in your browser. How the math works Pick a Length unit (metres by default) and choose what to Solve for: Hypotenuse c (the longest side, opposite the right angle) or one of the shorter sides, Leg a or Leg b. Enter the two sides you know. The calculator uses a² + b² = c², so c = √(a² + b²) or a missing leg = √(c² − other leg²). The hypotenuse must be longer than the leg you enter, and the triangle must have a 90° corner. The formula: a² + b² = c². In a right triangle, a and b are the two shorter sides and c is the longest side (opposite the right angle).