📏 Right Triangle Calculator
Enter the two legs of a right triangle to find its hypotenuse, area, perimeter, and angles.
units
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The Pythagorean theorem
For any right triangle, the square of the hypotenuse equals the sum of the squares of the two legs: c² = a² + b². This calculator uses that relationship to find the hypotenuse, then derives the area, perimeter, and the two acute angles.
How the angles are found
Once the hypotenuse is known, the acute angle opposite leg a is found with the inverse tangent of a/b, and the other acute angle is simply 90 degrees minus that value, since the two non-right angles of a right triangle always add up to 90 degrees.
Enter both legs in the same unit of length. This tool is intended for general math, school, and planning use.
Last reviewed August 2026