Math.log()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

La función Math.log() devuelve la base neutral de un número (base e)

\forall x > 0, \mathtt{\operatorname{Math.log}(x)} = \ln(x) = \text{el unico} ; y ; \text{tal que} ; e^y = x

La función en JavaScrcrip Math.log() es equivalente a ln(x) en matematicas.

Pruébalo

function getBaseLog(x, y) {
  return Math.log(y) / Math.log(x);
}

// 2 x 2 x 2 = 8
console.log(getBaseLog(2, 8));
// Expected output: 3

// 5 x 5 x 5 x 5 = 625
console.log(getBaseLog(5, 625));
// Expected output: 4

Sintaxis

Math.log(x)

Retorna el valor

La base natural (base e) del número dado. Si el número es negativo, se devuelve NaN

Descripcion

If the value of x is negative, the return value is always NaN.

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

If you need the natural log of 2 or 10, use the constants Math.LN2 or Math.LN10 . If you need a logarithm to base 2 or 10, use Math.log2() or Math.log10() . If you need a logarithm to other bases, use Math.log(x) / Math.log(otherBase) as in the example below; you might want to precalculate 1 / Math.log(otherBase) .

Examples

Using `Math.log()`

Math.log(-1); // NaN, out of range
Math.log(0); // -Infinity
Math.log(1); // 0
Math.log(10); // 2.302585092994046

Using `Math.log()` with a different base

The following function returns the logarithm of y with base x (ie. $\log_x y$ ):

function getBaseLog(x, y) {
  return Math.log(y) / Math.log(x);
}

If you run getBaseLog(10, 1000) it returns 2.9999999999999996 due to floating-point rounding, which is very close to the actual answer of 3.

Especificaciones

Specification
ECMAScript® 2026 Language Specification # sec-math.log