Skip to content

Geometry · free · no sign-up

Pythagorean calculator

Find the missing side of a right triangle from the other two.

How it works Report a problem

Pythagorean calculator

Enter your values below and press Calculate to see your result instantly.

Vector Selection (aĀ² + bĀ² = cĀ²)
Leave exactly ONE field blank/empty to compute its value automatically.
Computed Missing Vector
c = 5.00
GEOMETRIC TRIANGLE AREA
6.0
TOTAL PERIMETER
12.0
Solving for the Hypotenuse (c).

About the Pythagorean calculator

Find the missing side of a right triangle from the other two.

How to use the Pythagorean calculator

  1. Enter the two sides you know: Side A (Leg), Side B (Leg) or Side C (Hypotenuse).
  2. Leave the side you want to find empty.
  3. Press Calculate Missing Side.

Formula and method

aĀ² + bĀ² = cĀ². Hypotenuse: c = āˆš(aĀ² + bĀ²). Leg: a = āˆš(cĀ² āˆ’ bĀ²).

Worked example

Legs of 3 and 4 give a hypotenuse of 5.

Tips

  • The hypotenuse is always the longest side.
  • Common triples: 3-4-5, 5-12-13, 8-15-17.

Frequently asked questions

Does this work for any triangle?
Only right triangles. Other triangles need the law of cosines.