Number.MAX_SAFE_INTEGER

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The Number.MAX_SAFE_INTEGER static data property represents the maximum safe integer in JavaScript (253 – 1).

For larger integers, consider using BigInt.

Try it

const x = Number.MAX_SAFE_INTEGER + 1;
const y = Number.MAX_SAFE_INTEGER + 2;

console.log(Number.MAX_SAFE_INTEGER);
// Expected output: 9007199254740991

console.log(x);
// Expected output: 9007199254740992

console.log(x === y);
// Expected output: true

Value

9007199254740991 (9,007,199,254,740,991, or ~9 quadrillion).

Property attributes of Number.MAX_SAFE_INTEGER
Writableno
Enumerableno
Configurableno

Description

Double precision floating point format only has 52 bits to represent the mantissa, so it can only safely represent integers between -(253 – 1) and 253 – 1. "Safe" in this context refers to the ability to represent integers exactly and to compare them correctly. For example, Number.MAX_SAFE_INTEGER + 1 === Number.MAX_SAFE_INTEGER + 2 will evaluate to true, which is mathematically incorrect. See Number.isSafeInteger() for more information.

Because MAX_SAFE_INTEGER is a static property of Number, you always use it as Number.MAX_SAFE_INTEGER, rather than as a property of a number value.

Examples

Return value of MAX_SAFE_INTEGER

js
Number.MAX_SAFE_INTEGER; // 9007199254740991

Relationship between MAX_SAFE_INTEGER and EPSILON

Number.EPSILON is 2-52, while MAX_SAFE_INTEGER is 253 – 1 — both of them are derived from the width of the mantissa, which is 53 bits (with the highest bit always being 1). Multiplying them will give a value very close — but not equal — to 2.

js
Number.MAX_SAFE_INTEGER * Number.EPSILON; // 1.9999999999999998

Specifications

Specification
ECMAScript® 2025 Language Specification
# sec-number.max_safe_integer

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
MAX_SAFE_INTEGER

Legend

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Full support
Full support

See also