Overview
What Is a Log Calculator?
This tool calculates the logarithm of a number in any base, including common (base 10) and natural (base e) logarithms.
Calculate logarithms in any base instantly.
This tool calculates the logarithm of a number in any base, including common (base 10) and natural (base e) logarithms.
Useful for coursework involving exponential and logarithmic functions.
Input the value you want the logarithm of.
Input the base (10 for common log, or any other base).
The logarithm updates automatically.
It's the inverse of exponentiation - log_b(x) answers what power b must be raised to, to equal x.
Log typically means base-10 logarithm; ln specifically means natural logarithm (base e).
No, logarithms are undefined for negative numbers and zero in standard real-number math.
Commonly used in computer science, particularly in algorithms and information theory.
Using the change of base formula: log_b(x) = ln(x) / ln(b).
Log of 1 in any base equals 0, since any number to the power of 0 is 1.
No, calculations happen entirely in your browser.
pH scale, earthquake magnitude (Richter scale), and sound decibels all use logarithmic scales.
Yes, as long as it's positive and not equal to 1.
Yes, completely free with no sign-up required.