Base12

Base12, also called the duodecimal or dozenal system, is a positional numeral system that uses twelve as its base. It employs twelve digits, usually 0–9 plus two additional symbols for ten and eleven. A number written in base12 is interpreted by weighting each digit by powers of 12; for example, 1X in base12 equals 1×12 + 10 = 22 in decimal.

Digits beyond nine are not standardized; common conventions use X for ten and E for eleven, while others use T and E or A and B. The exact symbol set varies by context, but the concept remains the same.

Historically, base12 appears in many traditional measures and timekeeping: a dozen (12) units per grouping, a gross (12×12), 12 months in a year, and 12 hours on a clock. These practices have made duodecimal reasoning appealing for certain calculations and conversions.

Advantages: The base12 system has a high divisibility by 2, 3, 4, and 6, which yields finite representations for many fractions, such as 1/3 = 0.4 in base12. Proponents argue that this can simplify some arithmetic and measurements. Limitations: Decimal is globally dominant in education, commerce, science, and computing, and extensive base12 adoption faces compatibility and standardization challenges.

Modern usage is mostly limited to enthusiasts and niche applications; organizations such as the Dozenal Society promote education and potential reform. Dozens-based clocks, calendars, and measurement practices exist as curiosities or proposed systems rather than widespread standards.