Metric time is an alternative timekeeping system that uses 100 seconds per minute, 100 minutes per hour and 10 hours per day instead of the traditional 60 second per minute, 60 minutes per hour and 24 hours per day. A metric hour is 2.4 times longer than a current hour. Under the metric system, hours would become known as "decidays" and minutes would be "millidays." To use metric time, you would use a 100-minute clock.

Multiply the time by 2.4 to convert from metric hours to normal hours. For example, 7 metric hours would be equivalent to 16.8 regular hours. If you have a decimal, multiply the decimal by 60 to get the number of regular minutes. For example, 16.8 would convert to 16 hours and 48 minutes.

Divide the number of metric minutes times 1.44 to get the number of regular minutes. For example, 36 metric minutes would convert to 25 regular minutes.

Add the number of minutes from Step 1 with the number of minutes in Step 2. If the number is greater than 60, subtract 60 from the number of minutes and add one to the number of hours. For example, since 48 plus 25 is 73, the number of hours would go up one to 17 and the number of minutes would be 13.

Subtract 12 from the number of hours if the number of hours is 13 or greater and add "p.m." after the time. For example, 17:13 would become 5:13 p.m. If the number of hours is zero, add 12 to the number of hours and write "a.m." after the time. For example, 0:14 would become 12:14 a.m.