MDN wants to learn about developers like you: https://qsurvey.mozilla.com/s3/MDN-survey

The Number.MAX_SAFE_INTEGER constant represents the maximum safe integer in JavaScript (253 - 1).

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.

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.

Examples

Number.MAX_SAFE_INTEGER // 9007199254740991
Math.pow(2, 53) - 1     // 9007199254740991

Specifications

Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Number.MAX_SAFE_INTEGER' in that specification.
Standard Initial definition.
ECMAScript Latest Draft (ECMA-262)
The definition of 'Number.MAX_SAFE_INTEGER' in that specification.
Draft  

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support34 Yes31 No Yes9
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes31 Yes9 ?

See also

Document Tags and Contributors

 Last updated by: wbamberg,