Find the logarithm of a value to any base, with natural, base-10, and base-2 logs alongside. Enter the value and base.
Logarithm
—
To the given base.Usage Tip
log base 10 of a number is roughly its digit count minus one: 1000 has 4 digits and a log of 3.
THE MATH
log to base b of x = ln(x) ÷ ln(b)
The exponent the base is raised to in order to give x
The exponent the base is raised to in order to give x
A logarithm is the inverse of exponentiation: it asks what power produces a given number.
The change-of-base formula computes any base from natural logs.
The change-of-base formula computes any base from natural logs.
The value must be positive; the base must be positive and not 1.
Natural log (base e), base 10, and base 2 are always shown.
Logs turn multiplication into addition.
Natural log (base e), base 10, and base 2 are always shown.
Logs turn multiplication into addition.