JavaScript .MAX_SAFE_INTEGER

The .MAX_SAFE_INTEGER static data property represents the maximum safe integer in JavaScript, which is:

$$ 2^{53} - 1 = 9007199254740991 $$

It’s the largest integer that can be safely represented using the Number type without losing precision. This property is part of the Number class. To check if a value is a safe integer, use the .isSafeInteger() method. For integers larger than this limit, consider using the BigInt type instead.

Syntax

Number.MAX_SAFE_INTEGER;

Parameters:

None as it’s a static data property, not a function.

Return value:

Returns the largest safe integer representable by JavaScript’s Number type.

Example

This example demonstrates how .MAX_SAFE_INTEGER defines the upper limit for safe integers in JavaScript:

console.log(Number.MAX_SAFE_INTEGER);

console.log(Number.isSafeInteger(Number.MAX_SAFE_INTEGER));
console.log(Number.isSafeInteger(Number.MAX_SAFE_INTEGER + 1));

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The output produced by this code is:

9007199254740991
true
false

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Codebyte Example

A codebyte example showing why it’s best to avoid numbers larger than .MAX_SAFE_INTEGER:

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Both a and b evaluate to the same value because they exceed the maximum safe integer JavaScript can represent accurately. When numbers go beyond this limit, JavaScript starts to lose precision, which can lead to incorrect comparisons and unexpected results.