About this Pythagorean Theorem Calculator
Pythagorean Theorem Calculator finds the straight-line hypotenuse length when both perpendicular side lengths of a right triangle are known.
Formula or method
c = √(a² + b²).
Example
Sides 3 and 4 produce a hypotenuse of 5.
Common uses
- Check right-triangle geometry.
- Estimate diagonal distances.
- Verify construction or layout measurements.
How to use this tool
- Enter the values or text requested by the calculator.
- Choose units or options when the tool provides them.
- Select the calculation button and review the result.
- Use the formula, example and notes on this page to check whether the result fits your situation.
Important note
This formula applies to right triangles where a and b meet at a 90-degree angle.
Frequently asked questions
Does it work for every triangle?
No. The Pythagorean theorem in this form applies to right triangles.
Do the side units matter?
Use the same unit for both sides; the hypotenuse will use that same unit.