📐 Right Triangle Calculator
Fill any two fields (sides or angles) and click Calculate.
📋 Results
How to Use the Right Triangle Calculator
This free online tool solves any right triangle. Simply enter any two known values – two side lengths, or one side and one acute angle. The calculator instantly finds all missing sides, angles, area, and perimeter using the Pythagorean theorem and trigonometric ratios.
What is a Right Triangle?
A right triangle has one 90° angle. The sides are:
- Legs (a & b) – the two shorter sides that form the right angle.
- Hypotenuse (c) – the longest side, opposite the right angle.
Formulas Used
Pythagorean Theorem:
a² + b² = c²
Trigonometric ratios:
- sin(A) = opposite/hypotenuse = a/c
- cos(A) = adjacent/hypotenuse = b/c
- tan(A) = opposite/adjacent = a/b
Angle B = 90° – Angle A. The area is (a × b)/2, and the perimeter is a + b + c.
Example Cases
- Given a=3, b=4 → c=5, A≈36.87°, B≈53.13°
- Given a=5, c=13 → b=12, A≈22.62°, B≈67.38°
- Given b=8, A=30° → a≈4.6188, c≈9.2376
All calculations run directly in your browser – no data is sent anywhere.
