Math.log10()

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

$$\forall x > 0, \mathtt{\operatorname{Math.log10}(x)} = \log_10(x) = \text{the unique} \; y \; \text{such that} \; 10^y = x$$

Syntax

Math.log10(<var>x</var>)

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 equvalent 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

Browser compatibility

See also

• Math.exp()
• Math.log()
• Math.log1p()
• Math.log2()
• Math.pow()