Sine calculator

This calculator works out the sine of an angle. You can enter the angle in degrees or in radians; choose the unit next to the field.

What the sine function is

The sine of an angle in a right-angled triangle is the ratio of the length of the opposite side to the length of the hypotenuse. Imagine this triangle:

Then the sine of the angle β is equal to

$$\sin (\beta )=\frac{\text{length of the opposite side}}{\text{length of the hypotenuse}}=\frac{b}{a}$$

You can find more details in the article on trigonometric functions.