JavaScript (ES2026) reference · Math Methods and Constants

JavaScript Math.sin() Method

Return the sine of an angle given in radians. Convert degrees with deg * Math.PI / 180 first.

JavaScript (ES2026) Since ES1

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Syntax

Math.sin(x)

Parameters

Parameter	Description
`x`	An angle in radians.

Return value

A number between -1 and 1.

Examples

Degrees to radians firstTry it yourself

const rad = (deg) => (deg * Math.PI) / 180;
console.log(Math.sin(rad(30)).toFixed(4), Math.sin(rad(90)));

Output

0.5000 1

Points on a circleTry it yourself

const points = [0, 1, 2, 3].map((i) => {
  const a = (i * Math.PI) / 2;
  return [Math.round(Math.cos(a)) || 0, Math.round(Math.sin(a)) || 0]; // || 0 turns -0 into 0
});
console.log(points);