Trigonometry Calculator
Find trig function values for an angle, or solve a right-angled triangle from two sides.
| sin | – |
|---|---|
| cos | – |
| tan | – |
| cosec (1/sin) | – |
| sec (1/cos) | – |
| cot (1/tan) | – |
Trigonometry calculator
This trigonometry calculator does two jobs. The first tab gives you all six trigonometric ratios — sine, cosine, tangent, and their reciprocals cosecant, secant, and cotangent — for any angle in degrees or radians. The second tab solves a right-angled triangle: enter the two legs and it finds the hypotenuse, both non-right angles, and the area.
The basic trig ratios
In a right-angled triangle, sine = opposite ÷ hypotenuse, cosine = adjacent ÷ hypotenuse, and tangent = opposite ÷ adjacent — often remembered as SOH-CAH-TOA. The reciprocal ratios are cosecant (1/sin), secant (1/cos), and cotangent (1/tan). The hypotenuse is found with Pythagoras' theorem, c² = a² + b².
Degrees vs radians
Angles can be measured in degrees (a full circle is 360°) or radians (a full circle is 2π). School trigonometry usually uses degrees, while calculus and higher maths use radians. Use the unit selector to switch — to convert manually, multiply degrees by π/180 to get radians.
Frequently asked questions
Why is tan(90°) undefined?
Because tan = sin ÷ cos, and cos(90°) = 0. Dividing by zero is undefined, so the calculator reports "undefined" at those angles.