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


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.


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


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.
Living Standard  

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic Support34 (Yes)31 No (Yes)9
FeatureAndroidChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic Support (Yes) (Yes) (Yes)31 No (Yes)9

See also

Document Tags and Contributors

 Last updated by: indolering,