Right triangle calculator
Enter any two of the sides or acute angles of a right triangle and the rest is solved at once. Handy for students, builders and anyone measuring a slope or height.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter leg a (opposite angle a), leg b (opposite angle b), hypotenuse c, angle a and angle b.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Legs a and b, hypotenuse c: c² = a² + b², sin A = a / c, cos A = b / c, tan A = a / b, and B = 90° - A. Area = a × b / 2.
Example
Inputs: Leg a (opposite angle A) = 3, Leg b (opposite angle B) = 4. Result: Hypotenuse c: 5; Side a: 3; Side b: 4.
Limits and caveats
- Use one length unit for all sides. The area comes out in that unit squared.
- Angles are in degrees, and the right angle is the one opposite the hypotenuse.
Questions about this tool
How many values do I need to solve a right triangle?
Two are enough as long as one of them is a side, because the right angle is already known.
Why are two angles not enough?
Angles fix the shape but not the size, so infinitely many similar triangles share the same angles.
Which side is a?
Side a is opposite angle A, side b is next to it, and the hypotenuse is the longest side, opposite the right angle.