/JavaScript

Math.log2()

The Math.log2() static method returns the base 2 logarithm of a number. That is

$β x > 0 , πΌπππ.ππππΈ ( π‘ ) = log 2 ( x ) = the unique y such that 2 y = x \forall x > 0,;\mathtt{\operatorname{Math.log2}(x)} = \log_2(x) = \text{the unique } y \text{ such that } 2^y = x$

Syntax

js
Math.log2(x)


Parameters

x

A number greater than or equal to 0.

Return value

The base 2 logarithm of x. If x < 0, returns NaN.

Description

Because log2() is a static method of Math, you always use it as Math.log2(), 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(2). For log2(e), use the constant Math.LOG2E, which is 1 / Math.LN2.

Examples

Using Math.log2()

js
Math.log2(-2); // NaN
Math.log2(-0); // -Infinity
Math.log2(0); // -Infinity
Math.log2(1); // 0
Math.log2(2); // 1
Math.log2(3); // 1.584962500721156
Math.log2(1024); // 10
Math.log2(Infinity); // Infinity


Browser compatibility

Desktop Mobile Server
Chrome Edge Firefox Opera Safari Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet WebView Android Deno Node.js
log2 38 12 25 25 8 38 25 25 8 3.0 38 1.0 0.12.0