Enter the two legs of a right triangle to find its hypotenuse, angles, area, and perimeter.
How to Use the Right Triangle Calculator
The two legs are the only required fields — every other measurement, hypotenuse, both angles, area, perimeter, derives from just those two.
Two legs are all it takes to pin down a right triangle completely — hypotenuse, both acute angles, area, perimeter, everything follows. This Right Triangle Calculator works it all out from just a and b.
c = √(a² + b²)
angle A = arctan(a ÷ b), angle B = 90° − angle A
area = ½ × a × b, perimeter = a + b + cThe angle math leans on something that's always true for a right triangle: all three angles sum to 180°, one of them is locked at 90°, so the remaining two always add up to exactly 90° between them. Find one with arctan and the other falls out by simple subtraction. Area skips the usual "find the height" step entirely, because the two legs are already perpendicular — either one can serve as the base, the other as the height, no extra measurement needed.