Trigonometry calculator
Calculate the sine, cosine and tangent of an angle and convert degrees to radians.
In radians: 0.523599 rad
sin
0.5
sin0.5
cos0.866025
tan0.57735
Calculations are based on Estonia's tax rates in force for 2026. Results are informational.
Last updated: 2026-06-03
Trigonometric functions
Sine, cosine and tangent describe the relationship between an angle and the sides of a right triangle. The tangent is undefined when the cosine is zero (90°, 270°). Radians = degrees × π / 180.
How it is calculated
Formula
angle in radians = degrees × π ÷ 180. sin, cos, tan are computed from this angle; tan is undefined when cos = 0 (90° + 180°·k).
Example
30° → sin 0.5; cos ≈ 0.866; tan ≈ 0.577.
Frequently asked questions
How do I convert degrees to radians?+
Multiply the degrees by π ÷ 180. For example, 180° = π radians.
Why is the tangent sometimes undefined?+
The tangent is undefined when the cosine is zero, i.e. at angles 90° + 180°·k.