How can I remove trailing zeros from a number in JavaScript?

Angelos Chalaris · JavaScript, Math · May 8, 2022

JavaScript provides a couple of ways to format numeric values to a given precision. Namely, you can use Number.prototype.toFixed() and Number.prototype.toPrecision() to similar effect. However, neither of them deals with trailing zeros in the decimal part. Here's a few ways you can remove them:

Regular expression

Provided that the number is converted to a fixed-point string, you can use a regular expression to remove trailing zeros. All you have to do is match the decimal point (\.) and replace any zeros after it (0+) until the end of the string ($).

const toFixedWithoutZeros = (num, precision) =>
  num.toFixed(precision).replace(/\.0+$/, '');

toFixedWithoutZeros(1.001, 2); // '1'
toFixedWithoutZeros(1.500, 2); // '1.50'

The main issue with this approach is that the regular expression will only remove trailing zeros if the decimal part has no other digits before them. Writing a regular expression to remove trailing zeros from any number is a bit more involved and gets harder to read. Thus, this approach is discouraged.

Multiply by 1

A better way to remove trailing zeros is to multiply by 1. This method will remove trailing zeros from the decimal part of the number, accounting for non-zero digits after the decimal point. The only downside is that the result is a numeric value, so it has to be converted back to a string.

const toFixedWithoutZeros = (num, precision) =>
  `${1 * num.toFixed(precision)}`;

toFixedWithoutZeros(1.001, 2); // '1'
toFixedWithoutZeros(1.500, 2); // '1.5'

Number.parseFloat

Similar to the previous approach, you can use Number.parseFloat() to remove trailing zeros from a number. This method also accounts for non-zero digits after the decimal point. We recommend this approach as it's the most readable.

const toFixedWithoutZeros = (num, precision) =>
  `${Number.parseFloat(num.toFixed(precision))}`;

toFixedWithoutZeros(1.001, 2); // '1'
toFixedWithoutZeros(1.500, 2); // '1.5'

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