duodecimal

Duodecimal, or base-12, is a positional numeral system that uses twelve as its base. Like decimal, numbers are represented with digits and place values that are powers of 12. A common digit set consists of the ten decimal digits 0–9 plus two additional symbols to represent ten and eleven. Different conventions use different symbols, such as T and E or X and E, to avoid confusion with hexadecimal.

Historically, base-12 has attracted attention because many common fractions have terminating representations in base-12. For example, 1/3 is 0.4 in base-12, and 1/4 is 0.3. The dozen, and multiples such as the gross (144), appear in various measurement traditions. Although not widely adopted as the standard system, dozenal ideas have influenced some timekeeping and measurement schemes, and have been proposed for general arithmetic and education.

Advantages of the duodecimal system include easier division by factors of 2, 3, 4, and 6, and potentially more compact representations for a range of fractions. Drawbacks include the lack of universal standardization and limited compatibility with the globally dominant decimal system, which complicates teaching, computing, and data interchange. These factors have limited its mainstream adoption despite its mathematical appeal.

Today, base-12 remains primarily of interest to enthusiasts, educators, and researchers. Dozenal societies promote its study and promotion, while decimal remains the standard in most scientific, commercial, and computing contexts.