On this page is a *logarithm base 10 calculator*. Enter a number to take the *decadic* or *common* logarithm, and we’ll return the result.

To compute other logarithms, try another calculator or the generic logarithm tool:

## Common Logarithm Calculator

**Table of Contents**show ▼

## What is the Common Logarithm?

The *common logarithm* is a logarithm which uses base 10. It’s also known as the *decadic logarithm* or simply *log base 10*.

In the common logarithm, you ask “how many times do you have to raise the number 10 to equal a number x?”. In this case, the base b is 10, and fixed for this type of logarithm (similar to log base 2 and natural logarithm calculations).

## Common Logarithm Formula

The formula for the common logarithm is:

Where:

- 10: the base of the equation (we raise 10 to the yth power to get x)
- x: the argument; the number we need 10^y to equal
- y: the power or exponent we need to find

Note that the common logarithm is written a few ways:

Note that “Log” and “log” are ambiguous; if you are writing something new use a different form. These forms can sometimes mean the natural logarithm, instead.

### Decadic Logarithm Example

For example, let’s say you wanted to find the log base 10 of 1000. Here’s how it’d look:

In this case you need to raise 10 to the 3rd power to get 1000.

## Using the Common Logarithm Calculator

You only need to a single numbers to get the common logarithm: the argument **x**. Enter that to match a form of “log base 10 of x”.

When finished, hit **Compute Log Base 10**.

*Also try our other tools and calculators.*