Number

`Number.prototype.toPrecision`

Returns a string representing the Number object to the specified precision

Syntax

JavaScript

number.toPrecision(precision?)

Parameters

Parameter	Type	Description
precision	number	An integer specifying the number of significant digits (1-100)

Return Value

A string representing the number to the specified precision

Examples

Basic Usage

const num = 123.456;
console.log(num.toPrecision(5)); // '123.46'
console.log(num.toPrecision(2)); // '1.2e+2'

Practical Example

console.log((0.00123).toPrecision(2)); // '0.0012'
console.log((123.456).toPrecision(7)); // '123.4560'

Advanced Usage

const pi = Math.PI;
console.log(pi.toPrecision(4)); // '3.142'
console.log(pi.toPrecision(10)); // '3.141592654'

Understanding Number.prototype.toPrecision

The Number.prototype.toPrecision method in JavaScript returns a string representing the Number object to the specified precision. It belongs to the Number object and is one of the most widely used methods for working with number values in modern JavaScript and TypeScript applications.

The method signature is number.toPrecision(precision?). It accepts 1 parameter: precision. When called, it returns a string representing the number to the specified precision. Understanding when and how to use toPrecision() helps you write more expressive, readable code.

Common use cases for Number.prototype.toPrecision include data transformation, input validation, API response processing, and building reusable utility functions. It works well alongside related methods like number-tofixed, number-toexponential, number-tostring, enabling you to chain operations together for complex data manipulation pipelines.

Browser support for Number.prototype.toPrecision is excellent across all modern browsers including Chrome, Firefox, Safari, and Edge. It is also fully supported in Node.js and Deno. For older environments, transpilation with Babel or a polyfill may be needed.