Right Triangle Calculator

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Right Triangle Calculator

Solve a right triangle from two sides, or from one leg and the hypotenuse, using the Pythagorean theorem and right-triangle identities.

Last updated: June 2026 | By Patchworkr Team

Math check: c^2 = a^2 + b^2, with acute angles found from inverse trig.
Result
Enter a real number.

Formulas

c = sqrt(a^2 + b^2)
A = ab / 2
h = ab / c
r = (a + b - c) / 2
R = c / 2

The acute angles are the two non-right angles in the triangle, and they always add to 90 degrees.

How to Use It

  1. Choose whether you know two legs or one leg plus the hypotenuse.
  2. Enter positive real numbers only.
  3. Read the solved side lengths, angles, and derived measurements in the result panel.

Worked Example

For legs 3 and 4, the hypotenuse is sqrt(3^2 + 4^2) = 5.

The area is 3 x 4 / 2 = 6, the altitude to the hypotenuse is 12 / 5 = 2.4, and the angles are about 36.87 degrees and 53.13 degrees.

Notes

This calculator assumes a standard right triangle with a 90-degree angle and positive side lengths. The hypotenuse must always be longer than either leg.

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