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.

See also mantissa.