The long and short scales are two of several naming systems for integer powers of ten which use some of the same terms for different magnitudes.

For whole numbers smaller than 1,000,000,000 (109), such as one thousand or one million, the two scales are identical. For larger numbers, starting with 109, the two systems differ. For identical names, the long scale proceeds by powers of one million, whereas the short scale proceeds by powers of one thousand. For example, one billion is one thousand millions in the short scale, while it is one million millions in the long scale. The long scale system introduces new terms for the intervening values, typically replacing the word ending -ion with -iard.