Math.trunc()

Cuts off the fractional part of a number, leaving the integer part.

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Example

JavaScript

console.log(Math.trunc(4.9))
console.log(Math.trunc(-4.9))
console.log(Math.floor(-4.9))
console.log(Math.trunc(7.25 * 60))

Console

-4

-5

435

The Math.trunc() function removes everything after the decimal point, without rounding. Math.trunc(4.9) is 4, and Math.trunc(-4.9) is -4.

It differs from Math.floor() with negative numbers: floor rounds down (further from zero), while trunc always rounds toward zero.

It’s a good choice when you just want to "pull out" the integer part, for example full hours from a decimal number, regardless of sign.

Math.trunc(x)

Parameter	Type	Description
x	number	The number whose fractional part you want to cut off.

Widely available

Works in all modern browsers, phones included. You can use it without worry.

With negative numbers, choose deliberately between trunc (toward zero) and floor (down).
To convert text into an integer, use Number.parseInt(), not Math.trunc() on a string.

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