FreeNo signup
Pythagorean Theorem Calculator
Find the hypotenuse from two legs or a missing leg from the hypotenuse and another leg. Also calculate the right triangle's area and perimeter.
- Hypotenuse
- 5
- Area
- 6 square units
- Perimeter
- 12
How the calculation works
Pythagoras' theorem: a² + b² = c². The hypotenuse is c = √(a² + b²), and a missing leg is b = √(c² − a²). Area S = ab/2.
Inputs
- Find
- First leg a
- Second leg b or hypotenuse c
Calculation details
Use the same unit for both lengths. Legs of 3 and 4 give a hypotenuse of 5, perimeter 12, and area 6 square units.
The formula applies only to right triangles. The hypotenuse must be longer than either leg; equal values do not form a triangle.
Related calculators
- Aspect Ratio Calculatoraspect ratio calculatorOpen →
- Average Calculatoraverage calculatorOpen →
- Circle Area Calculatorcircle area calculatorOpen →
- Cylinder Volume Calculatorcylinder volume calculatorOpen →
- Fraction Calculatorfraction calculatorOpen →
- GPA Calculatorgpa calculatorOpen →
Other sections
Updated: 2026-10-02