What This Calculator Does

This Pythagorean theorem calculator is built specifically for right-triangle tasks. Instead of trying to solve every possible triangle case, it focuses on four very practical jobs: find the hypotenuse from two legs, find one leg from the hypotenuse and the other leg, or verify whether three sides satisfy the right-triangle relationship.

That narrow focus is a strength. In classwork, layout checks, carpentry, room measurements, screen sizing, and diagonal estimates, the real question is often not "solve the entire triangle." It is simply "does this form a right angle?" or "what should the missing side be?" This page is designed for that exact layer of work.

When to Use It

• You know two sides of a right triangle and want the third.
• You want to test whether three sides satisfy a^2 + b^2 = c^2.
• You are doing classroom practice, carpentry, renovation layout, or diagonal measurement.
• You want a faster right-angle check than doing the arithmetic by hand.

Inputs Explained

Calculation Mode

The page has four modes, and the editable fields change with the mode. Start by deciding whether you are filling in a missing side or verifying a full side set. That small step prevents a lot of input mistakes.

Legs a and b

a and b are the two perpendicular sides. They must be positive, and they must use the same unit system as c. The page does not convert between centimeters, inches, or meters for you.