The U.S. military uses 24-hour military time to avoid confusion between a.m. and p.m. The Navy started using it in 1920, and ...

Military time is based on a 24 hour clock instead of using the standard 12 hour clock. Convert standard time to 24 hour time with our military time chart.

Early mechanical clocks showed all 24 hours, but over time, clockmakers found the 12-hour system simpler and cheaper. Of course, a.m. stands for ante meridiem, which is Latin for "before midday." ...