# Characteristic

The characteristic of a common logarithm (that is, a base 10 logarithm) is its integer part, which indicates the order of magnitude but not the digits of the number.

For example, the characteristic of $\log_{10} 20 \approx 1.3010$ is $1$ while the characteristic of $\log_{10} 600 \approx 2.7782$ is $2$.

Note that the characteristic of $\log_{10} 0.2 \approx -0.6990$ is $-1$, as we always round down to find the characteristic.