Convert a BigInt to a Number in JavaScript

Apr 25, 2023

BigInts are a new primitive type in JavaScript that can contain arbitrarily large integers. You can convert a BigInt to its corresponding number representation using the Number() function as follows:

const answerBigInt = 42n;

const answerNum = Number(answerBigInt);

typeof answerNum; // 'number'
answerNum === 42; // true

Keep in mind that, if the BigInt is larger than Number.MAX_VALUE or smaller than Number.MIN_VALUE, Number(bigint) will be positive or negative infinity.

const tooBig = Number(10n**10000n);
tooBig === Number.POSITIVE_INFINITY; // true
tooBig; // Infinity

const tooSmall = Number((-10n)**10001n);
tooSmall === Number.NEGATIVE_INFINITY; // true
tooSmall; // -Infinity

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