JavaScript (ES2026) reference · Number Methods and Properties

JavaScript Number.isSafeInteger() Method

Return true if a value is an integer that can be represented exactly, between -(2^53 - 1) and 2^53 - 1.

JavaScript (ES2026) Since ES2015

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

Syntax

Number.isSafeInteger(value)

Parameter	Description
`value`	The value to test.

true or false.

The safe rangeTry it yourself

console.log(Number.isSafeInteger(2 ** 53 - 1), Number.isSafeInteger(2 ** 53));

Output

true false

Use BigInt beyond itTry it yourself

console.log(2 ** 53 === 2 ** 53 + 1); // precision is lost
console.log(2n ** 53n === 2n ** 53n + 1n); // BigInt is exact

Output

true
false

Version	Change
JavaScript ES2015	Added

Number.MAX_SAFE_INTEGER · The largest integer JavaScript numbers can represent exactly: 2^53 - 1, or 9,007,199,254,740,991.
Number.isInteger() · Return true if a value is a number with no fractional part. Strings aren't converted, so Number.isInteger("5") is false.
JavaScript Numbers · tutorial
JavaScript Type Conversion · tutorial