Sine Calculator

How it works

1. 1Enter an angle value and choose degrees or radians using the unit toggle.
2. 2The calculator applies sin(θ) — converting degrees to radians internally when needed — and returns a value between −1 and 1.
3. 3Results are formatted to 6 figures; exact multiples of 90° (where sine is 0, 1, or −1) snap to their true values.

Use cases

• Physics and engineering problems involving wave motion, oscillation, and AC circuits.
• Geometry and surveying: finding the side opposite a known angle in a right triangle.
• Verifying homework or exam answers for trigonometry, precalculus, and calculus.

Frequently asked questions

What does sine mean geometrically?

In a right triangle, sin(θ) is the side opposite the angle divided by the hypotenuse. On the unit circle it is the y-coordinate of the point at angle θ, so its value is always between −1 and 1.

Why does sin(90°) equal 1?

At 90° the opposite side equals the hypotenuse, so the ratio is 1. On the unit circle the point is at the top (0, 1), confirming sin(90°) = 1.

When should I use radians instead of degrees?

Radians are the natural unit in calculus and most programming languages. Use them for derivatives, integrals, Fourier analysis, or any formula where the angle sits inside a transcendental function.