Pythagorean Theorem Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserBasic
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter any two sides of a right-angled triangle.
- Press Calculate for the third side.
How it works
For a right-angled triangle, a² + b² = c², where c is the hypotenuse (the longest side). Enter any two sides and the calculator finds the missing one.
Worked example
Sides 3 and 4. c = √(3² + 4²) = √25 = 5.
Frequently asked questions
Does it only work for right triangles?
Yes — the theorem applies to right-angled triangles only.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.