---
title: "How to Understand the Safe Integer Limit in JavaScript"
url: https://daily.dev/posts/how-to-understand-the-safe-integer-limit-in-javascript-4vq0h3lnj
source_url: https://www.freecodecamp.org/news/how-to-understand-the-safe-integer-limit-in-javascript
type: article
source: "freeCodeCamp"
published: 2026-06-03T23:26:32.323Z
updated: 2026-06-03T23:26:55.761Z
tags: ["javascript"]
reading_time: 5
upvotes: 5
comments: 2
language: en
---

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# How to Understand the Safe Integer Limit in JavaScript

**[freeCodeCamp](https://daily.dev/sources/freecodecamp)** · 5 min read · 5 upvotes · 2 comments

## Summary

JavaScript uses IEEE 754 double-precision floating-point to store numbers, which limits safe integer representation to ±9007199254740991 (Number.MAX_SAFE_INTEGER). Beyond this limit, integers lose precision — for example, MAX_SAFE_INTEGER + 1 and MAX_SAFE_INTEGER + 2 produce the same result. This can cause serious bugs in financial systems, analytics platforms, distributed IDs, and blockchain applications. The BigInt type solves this by supporting arbitrary-precision integers using the 'n' suffix or BigInt() constructor. Key caveats: BigInt cannot be mixed with Number without explicit conversion, doesn't support decimals, and is slower than regular Number arithmetic. Use BigInt when integer precision is critical; stick with Number for everyday calculations.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://www.freecodecamp.org/news/how-to-understand-the-safe-integer-limit-in-javascript>

## Community discussion

Top comments from developers on daily.dev.

**@allinonetools** · 1 upvotes

> Learned this the hard way when working with large IDs — once you cross the safe integer limit, things start breaking in ways that are really hard to spot. BigInt is a lifesaver when exact values matter.

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