Number.MAX_SAFE_INTEGER

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

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
Number.MAX_SAFE_INTEGER * Number.EPSILON // 2 because in floating points, the value is actually the decimal trailing "1"
                                         // except for in subnormal precision cases such as zero

Polyfill

if (!Number.MAX_SAFE_INTEGER) {
    Number.MAX_SAFE_INTEGER = Math.pow(2, 53) - 1; // 9007199254740991
}

Specifications

Browser compatibilityUpdate compatibility data on GitHub

See also

• Number.MIN_SAFE_INTEGER
• Number.isSafeInteger()