Sine Calculator

This sine calculator works out the sine of any angle you enter, whether you are checking triangle geometry, plotting a wave, or need a quick trig value without reaching for a scientific calculator. Sine is one of the six trigonometric functions: in a right triangle it is the ratio of the side opposite the angle to the hypotenuse, and on the unit circle it is the y-coordinate for that angle. You enter the angle as a number and choose whether it is in degrees or radians from the dropdown. The calculator converts your angle to radians internally, because that is the unit the underlying maths uses, then evaluates the sine and returns it as the main result. Alongside the sine value, it also shows the angle expressed in both radians and degrees, so you can check you have selected the right unit and see the conversion at a glance. For example, entering 30 with degrees selected returns a sine of 0.5, and entering 90 degrees returns 1, both matching well known reference angles. Because sine is periodic, repeating every 360 degrees or 2 pi radians, angles that differ by a full rotation always give the same result. Use this tool for maths and physics homework, engineering and surveying calculations, navigation, or any time you need an accurate trig value fast.

Angle

Angle unit

0.5

Angle (radians)0.523599 rad

Angle (degrees)30 deg

The formula

Sine is the ratio of the side opposite the angle to the hypotenuse in a right triangle, and the y coordinate on the unit circle. The calculator computes sin of the angle in radians.

Worked example

Sine of 30 degrees is 0.5. Enter 30 with degrees selected to confirm, then try 90 degrees to get 1.

Frequently asked questions

How do I find the sine of an angle?

Enter the angle and pick degrees or radians. The calculator converts to radians and evaluates the sine.

Degrees or radians?

Either. Choose the unit in the dropdown. The angle is shown in both units beside the result so you can check.

Why is the result the same every 360 degrees?

The trig functions are periodic. Sine and cosine repeat every 360 degrees (2 pi radians), so equivalent angles give the same value.

Who this calculator is for

This calculator is for students, engineers, surveyors and anyone who needs the sine of an angle.

What this calculator assumes

You enter a single angle in the chosen unit.
The angle is converted to radians for the calculation.
Results are rounded for display.

Formula and sources

Related calculators

Trig Calculator: all six trig functions at once.
Degrees to Radians Calculator: convert angle units.
Right Angle Triangle Calculator: solve a right triangle.

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