JavaScript (ES2026) reference · Math Methods and Constants

JavaScript Math.ceil() Method

Round a number up to the next integer: Math.ceil(4.1) is 5 and Math.ceil(-4.1) is -4.

JavaScript (ES2026) Since ES1

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Syntax

Math.ceil(x)

Parameter	Description
`x`	A number.

An integer.

Round upTry it yourself

console.log(Math.ceil(4.1), Math.ceil(4), Math.ceil(-4.1));

Output

5 4 -4

Number of pagesTry it yourself

const items = 47, perPage = 10;
console.log("pages:", Math.ceil(items / perPage));

Output

pages: 5

Version	Change
JavaScript ES1	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.round() · Round a number to the nearest integer; halves round up towards +Infinity, so Math.round(-2.5) is -2.
Math.trunc() · Remove the fractional part of a number, rounding towards zero: Math.trunc(-4.7) is -4.
JavaScript Math · tutorial
JavaScript Numbers · tutorial