JavaScript (ES2026) reference · Math Methods and Constants

JavaScript Math.trunc() Method

Remove the fractional part of a number, rounding towards zero: Math.trunc(-4.7) is -4.

JavaScript (ES2026) Since ES2015

Create a free account to save this page, take notes and track your progress. Sign in

Syntax

Math.trunc(x)

Parameter	Description
`x`	A number.

An integer.

trunc() vs floor() for negativesTry it yourself

console.log(Math.trunc(4.7), Math.trunc(-4.7), Math.floor(-4.7));

Output

4 -4 -5

Integer division and remainderTry it yourself

console.log(Math.trunc(7 / 2), 7 % 2);

Output

3 1

Version	Change
JavaScript ES2015	Added

Math.floor() · Round a number down to the integer below it: Math.floor(4.9) is 4 and Math.floor(-4.1) is -5.
Math.ceil() · Round a number up to the next integer: Math.ceil(4.1) is 5 and Math.ceil(-4.1) is -4.
JavaScript Math · tutorial
JavaScript Numbers · tutorial