Trigonometry Calculator
Free trigonometry calculator — sin, cos, tan and their reciprocals for any angle, plus a right-triangle solver from two sides.
Everyday Uses
Math homework
Get sin, cos, tan and solve right triangles step by step.
Angles & heights
Find an unknown side or angle from the ones you know.
Building & DIY
Calculate ramps, roof angles, and diagonal bracing.
Navigation
Resolve distances and bearings into components.
Frequently Asked Questions
What are sine, cosine, and tangent?
In a right triangle, for a given angle: sine = opposite ÷ hypotenuse, cosine = adjacent ÷ hypotenuse, and tangent = opposite ÷ adjacent. The mnemonic SOH-CAH-TOA captures all three. For a 30° angle, sin = 0.5, cos ≈ 0.866, and tan ≈ 0.577.
How do you solve a right triangle?
With any two sides, use the Pythagorean theorem (a² + b² = c²) to find the third, then take the inverse tangent of opposite ÷ adjacent to get an angle. This calculator does it automatically: enter any two of the opposite, adjacent, and hypotenuse and it returns every side, both non-right angles, the area, and the perimeter.
What are cosecant, secant, and cotangent?
They are the reciprocals of the main three: cosecant (csc) = 1 ÷ sin, secant (sec) = 1 ÷ cos, and cotangent (cot) = 1 ÷ tan. They come up in calculus and physics but are just the flipped versions of sine, cosine, and tangent.