# The Number toPrecision() method

> Learn how the JavaScript Number toPrecision() method returns a string representing a number to a given number of significant digits, padding or rounding it.

Author: [Flavio Copes](https://flaviocopes.com/about/) | Published: 2019-03-21 | Topics: [JavaScript](https://flaviocopes.com/tags/js/) | Canonical: https://flaviocopes.com/javascript-number-toprecision/

This method returns a string representing the number to a specified precision:

```js
new Number(21.2).toPrecision(0) //error! argument must be > 0
new Number(21.2).toPrecision(1) //2e+1 (= 2 * 10^1 = 2)
new Number(21.2).toPrecision(2) //21
new Number(21.2).toPrecision(3) //21.2
new Number(21.2).toPrecision(4) //21.20
new Number(21.2).toPrecision(5) //21.200
```