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.
Table of contents
Table of ContentsPrerequisitesWhat Is the Safe Integer Limit in JavaScript?Why Is It Called a “Safe” Integer?How Can You Understand This Problem if You Are New to the Game?How to Check if a Number Is SafeCan Unsafe Integers Cause Any Problems?Introducing BigInt in JavaScriptFinal Thoughts10.6K Impressions2 Comments