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 September 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 | |
|---|---|
| Writable | no |
| Enumerable | no |
| Configurable | no |
Description
Double precision floating point format only has 52 bits to represent the Number.isSafeInteger() for more information.
As mentioned in Number.MAX_VALUE, which is approximately 1.7976931348623157 × 10308.
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
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.
Number.MAX_SAFE_INTEGER * Number.EPSILON; / 1.9999999999999998
Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-number.max_safe_integer |