Triangle Calculators

Use our Triangle Inequality Theorem Calculator to quickly verify whether three given side lengths can form a valid triangle—by checking the essential inequality conditions—with clear, step-by-step explanations.

Solve right triangles instantly with our Special Right Triangles Calculator! Supports 45°-45°-90°, 30°-60°-90°, b = 2a, b = 3a, and 3x-4x-5x triangles.

Find missing sides, scale factors, and verify triangle similarity using SSS, SAS, or AA with our Similar Triangles Calculator—complete with solutions!

Solve any equilateral triangle in seconds with our Equilateral Triangle Calculator! Enter one value to find side length, area, perimeter, height, or angles.

Solve 45-45-90 triangles instantly with our 45 45 90 Triangle Calculator! Find legs, hypotenuse, height, area, or perimeter from any one known value with steps.

Solve 30-60-90 triangles effortlessly with our 30 60 90 Triangle Calculator! Find the sides, altitude, area, or perimeter from any one known value—with steps.

Use our Pythagorean Theorem Calculator to find missing sides, area, perimeter, angles, or altitude of a right triangle—just enter any two known sides.