Web/JavaScript/Reference/Global objects/Math/log10

The Math.log10() function returns the base 10 logarithm of a number, that is

<math display="block">\forall x > 0,\mathtt{\operatorname{Math.log10}(x)} = \log_{10}(x) = \text{the\ unique}\; y\;\text{such\ that}\; 10^{y} = x</math>

Syntax

Math.log10(x)

Parameters

x: A number.

Return value

The base 10 logarithm of the given number. If the number is negative, NaN is returned.

Description

If the value of x is less than 0, the return value is always NaN.

Because log10() is a static method of Math, you always use it as Math.log10(), rather than as a method of a Math object you created (Math is not a constructor).

This function is the equivalent of Math.log(x) / Math.log(10). For log10(e) use the constant Math.LOG10E which is 1 / Math.LN10.

Examples

Using Math.log10()

Math.log10(2);      // 0.3010299956639812
Math.log10(1);      // 0
Math.log10(0);      // -Infinity
Math.log10(-2);     // NaN
Math.log10(100000); // 5

Polyfill

This can be emulated with the following function:

Math.log10 = Math.log10 || function(x) {
  return Math.log(x) * Math.LOG10E;
};

Specifications

Specification
ECMAScript (ECMA-262)The definition of 'Math.log10' in that specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
`log10`	Chrome Full support 38	Edge Full support 12	Firefox Full support 25	IE No support No	Opera Full support 25	Safari Full support 8	WebView Android Full support 38	Chrome Android Full support 38	Firefox Android Full support 25	Opera Android Full support 25	Safari iOS Full support 8	Samsung Internet Android Full support 3.0	nodejs Full support 0.12

Legend

Full support: Full support
No support: No support