Quick start
- Choose two legs mode or leg and hypotenuse mode.
- Enter the known side lengths.
- Add a unit label if useful.
- Press Calculate right triangle.
Choosing input mode
Use two legs mode when both shorter sides are known. The calculator finds the hypotenuse.
Use leg and hypotenuse mode when one leg and the longest side are known. The calculator finds the missing leg.
What the calculator returns
The calculator returns side lengths, area, perimeter, and the two acute angles. The third angle is always 90 degrees.
Area is reported in square units, while perimeter and side lengths use the length unit you entered.
When to use the simpler theorem tool
Use the Pythagorean Theorem Calculator when you only need one missing side.
Use this right triangle tool when you also need area, perimeter, and angles.
Examples from the calculator
c = 15
missing leg = 12
Area = 6
History, privacy, and copying
Recent answers stay visible in the page while you work. The history is kept only in the current browser tab and is not sent to a server.
Copy answer copies the expression and result so you can paste it into notes, homework, a message, or another document.