geometry calculator

Pythagorean Theorem Calculator

Find the missing side of a right triangle instantly. Perfect for construction, navigation, game development, physics or just solving homework problems.

Important Use Notice

Informational calculator only. Verify important outputs independently before legal, tax, medical, engineering, safety-critical, contractual, employment, or compliance use.

Estimate

Enter job values, review the estimate, then use the decision hints before ordering or quoting.

First leg of the right triangle

Second leg of the right triangle

Leave empty to calculate

Estimate Results

Enter values to see the result.

Check

Using wrong side as hypotenuse
Forgetting to square values

Example

Legs 3 and 4 → hypotenuse 5 (3-4-5 triangle)

Formula

c² = a² + b² (c = hypotenuse)

For missing hypotenuse: c = √(a² + b²). For missing leg: a = √(c² - b²).

Only valid for right triangles (90° angle)

Next Step

FAQ

Does this work for non-right triangles?

No — only for right triangles. Use law of cosines for others.

Can sides be decimals?

Yes — calculator handles floating-point precision.