JavaScript (ES2026) reference · Math Methods and Constants

JavaScript Math.log10() Method

Return the base-10 logarithm of a number, e.g. to count digits or work with decibels.

JavaScript (ES2026) Since ES2015

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Syntax

Math.log10(x)

Parameter	Description
`x`	A number.

A number.

Powers of tenTry it yourself

console.log(Math.log10(1000), Math.log10(0.01));

Output

3 -2

Count the digits of a positive integerTry it yourself

const digits = (n) => Math.floor(Math.log10(n)) + 1;
console.log(digits(7), digits(12345));

Output

1 5

Version	Change
JavaScript ES2015	Added

Math.log() · Return the natural logarithm (base e) of a number; divide by Math.log(base) to get a logarithm in any base.
Math.log2() · Return the base-2 logarithm of a number, e.g. how many bits or how many halvings are needed.
JavaScript Math · tutorial
JavaScript Numbers · tutorial