SHAPES, DATA, AND SCHOOL MATH
Right Triangle Calculator
Calculate the main measurements of a right triangle from the lengths of its two perpendicular legs.
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Enter your values and select Calculate. Your result stays on this device.
How it works
c = √(a² + b²); acute angles use inverse tangent; area = a × b ÷ 2.
Assumptions
The entered sides are the two perpendicular legs; displayed angles are in degrees.
About this calculator
Use this right triangle calculator when the search task goes beyond one missing side. A single calculation returns the hypotenuse, both acute angles, area, and perimeter.
How to use it
- Enter both perpendicular leg lengths in the same unit.
- Calculate the hypotenuse with the Pythagorean theorem.
- Review the two acute angles and confirm they total 90 degrees.
- Use the area and perimeter only after checking that the triangle is right-angled.
Use case
right triangle calculator: a clear planning check
Calculate the hypotenuse, both acute angles, area, and perimeter from two legs entered in one consistent unit.
Solve a right triangle from its two perpendicular legs, including side, angle, area, and perimeter results.
Method and update
Last reviewed: 2026-08-22. This tool performs the stated formula locally in your browser using the values you enter.
Frequently asked questions
Can two sides solve a right triangle?
Yes when the two known sides are the perpendicular legs. The remaining side and acute angles can then be calculated.
Do the acute angles add to 90 degrees?
Yes. Together with the right angle, all triangle angles total 180 degrees.
What units are used?
Use one consistent length unit. The side and perimeter results use that unit; area uses its square.
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