What is the sine function?

Sine is a fundamental trigonometric function. For a right triangle, sin(angle) equals the length of the opposite side divided by the hypotenuse. On a unit circle, it equals the y-coordinate of the point at that angle.

What is sin(90 degrees)?

sin(90°) = 1. This is the maximum value sine can reach. At 90 degrees the point on the unit circle is at the very top (0, 1), so the y-coordinate — and therefore sine — equals 1.

sin(0) = 0, whether the angle is 0 degrees or 0 radians. The point on the unit circle at angle 0 sits at (1, 0), giving a y-coordinate of 0.

What is the range of the sine function?

Sine always returns a value between -1 and 1 (inclusive). It equals 1 at 90°, 0 at 0° and 180°, and -1 at 270°.

How do I convert degrees to radians?

Multiply degrees by π/180. For example, 90° × (π/180) = π/2 ≈ 1.5708 radians. This calculator accepts both units directly, so you can skip manual conversion.

Why does sin(30°) = 0.5?

In a 30-60-90 right triangle the side opposite the 30° angle is exactly half the hypotenuse, so opposite/hypotenuse = 0.5. This is one of the most common exact values in trigonometry.

Sine Calculator

Name: Sine Calculator
Availability: InStock
Author: Nham Vu

Enter an angle in degrees or radians to instantly compute its sine value.

Calculate Sine

Angle Unit

Degrees Radians

Enter an angle above to see its sine value.

Unit Circle

The red dot marks the angle; the blue vertical line shows the sine value (y-projection).

Common Angles (degrees)

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