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Pythagorean Theorem Calculator
Solve right triangles for the hypotenuse or a missing leg, check Pythagorean triples and see the triangle area.
Pythagorean theorem calculator
Answer: —
Triple check: —
Area: —
How to use the Pythagorean Theorem Calculator
- Choose whether to find the hypotenuse or a missing leg.
- Enter the two known values in the boxes.
- Read the answer, the triple check and the triangle area below.
Features
- Finds the hypotenuse or either missing leg
- Checks whether the sides form a Pythagorean triple
- Also reports the right triangle area
- Instant results, all calculated locally
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Frequently Asked Questions
Common questions about the free online pythagorean theorem calculator.
In a right triangle the square of the hypotenuse equals the sum of the squares of the two
legs: a squared plus b squared equals c squared.
Choose the hypotenuse mode, enter the two legs and read the result. For legs 3 and 4 the
hypotenuse is exactly 5.
Pick the leg mode, enter the known leg and the hypotenuse, and the tool subtracts the square
of the leg from the square of the hypotenuse.
It is a set of three whole numbers that satisfy the theorem, such as 3-4-5, 5-12-13, 8-15-17
or 7-24-25.
No, the theorem only applies to right triangles. For other shapes use the triangle calculator
and the law of cosines.
Yes. Type decimal values and the answer is returned rounded to six decimal places, with the
area shown the same way.
No. Every calculation runs locally in your browser, so the numbers you type never leave your
device or reach a server.
Yes. The calculator is fully responsive and works on phones, tablets and desktop browsers
without installing anything.
Yes. The Pythagorean theorem calculator is completely free, with no account, no sign up and
no usage caps.
Last updated: October 10, 2026