The Number.MAX_SAFE_INTEGER
constant represents the maximum safe integer in JavaScript (253 - 1
).
For larger integers, consider using BigInt
.
Property attributes of Number.MAX_SAFE_INTEGER |
|
---|---|
Writable | no |
Enumerable | no |
Configurable | no |
Description
The MAX_SAFE_INTEGER
constant has a value of 9007199254740991
(9,007,199,254,740,991 or ~9 quadrillion). The reasoning behind that number is that JavaScript uses double-precision floating-point format numbers as specified in IEEE 754 and can only safely represent numbers between -(253 - 1)
and 253 - 1
.
Safe in this context refers to the ability to represent integers exactly and to correctly compare them. 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.
This field does not exist in old browsers. Using it without checking its existence, such as Math.max(Number.MAX_SAFE_INTEGER, 2)
, will yield undesired results such as NaN.
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
object you created.
Polyfill
if (!Number.MAX_SAFE_INTEGER) { Number.MAX_SAFE_INTEGER = 9007199254740991; // Math.pow(2, 53) - 1; }
Examples
Return value of MAX_SAFE_INTEGER
Number.MAX_SAFE_INTEGER; // 9007199254740991
Numbers higher than safe integer
This returns 2 because in floating points, the value is actually the decimal trailing "1" except for in subnormal precision cases such as zero.
Number.MAX_SAFE_INTEGER * Number.EPSILON; // 2
Specifications
Specification |
---|
ECMAScript (ECMA-262) The definition of 'Number.MAX_SAFE_INTEGER' in that specification. |
Browser compatibility
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
MAX_SAFE_INTEGER | Chrome Full support 34 | Edge Full support 12 | Firefox Full support 31 | IE No support No | Opera Full support 21 | Safari Full support 9 | WebView Android Full support ≤37 | Chrome Android Full support 34 | Firefox Android Full support 31 | Opera Android Full support 21 | Safari iOS Full support 9 | Samsung Internet Android Full support 2.0 | nodejs Full support 0.12 |
Legend
- Full support
- Full support
- No support
- No support