Math.floor
Rounds a number down to an integer.
Available since: ES1
Syntax
Math.floor(x)Parameters
| Parameter | Type | Description |
|---|---|---|
| x | number | The number to round. |
Return value
numberThe largest integer not greater than `x`.
Examples
Rounding down, including negative numbers:
console.log(Math.floor(4.7));
console.log(Math.floor(-4.7));Output:
4
-5Math.ceil() rounds up, and Math.trunc() drops the fraction:
console.log(Math.ceil(4.2));
console.log(Math.trunc(-4.7));Output:
5
-4Notes
For negative numbers "down" means further from zero: Math.floor(-4.7) gives -5.
See also
- Math.round — Rounds a number to the nearest integer.
- Math.random — Returns a random number between 0 and 1.
- Math.ceil — Rounds a number up to an integer.
- Math.trunc — Drops the fractional part of a number.
Related recipes
In the tutorial
- Numbers — Numbers in JavaScript — integers and fractions, rounding, the Math object, toFixed and the special values Infinity and NaN.