Decimal/Metric Time Clock
A live clock showing decimal (metric) time next to standard time — the French Revolutionary system that splits the day into 10, not 24.
About this tool
Decimal time divides the day into 10 decimal hours, each decimal hour into 100 decimal minutes, and each decimal minute into 100 decimal seconds — so a full day runs from 0:00:00.00 to 10:00:00.00 in base 100 throughout, rather than the familiar base-60/24 system. It was briefly used in France in the 1790s and has been proposed many times since as a cleaner, metric-style alternative to hours, minutes and seconds.
The conversion works by first finding what fraction of the day has passed since midnight: (hours×3600 + minutes×60 + seconds) / 86400. Multiplying that fraction by 10 gives the decimal hour; the fractional remainder is then multiplied by 100 to give decimal minutes, and the process repeats to give decimal seconds and centiseconds. Because decimal midday is exactly halfway through the day, standard noon (12:00:00) always converts to exactly 5:00:00.00 decimal, and 6:00am (one quarter of the way through the day) converts to exactly 2:50:00.00 decimal.
- Did anyone actually use decimal time?
- Yes — revolutionary France officially adopted decimal time in 1793–1794 alongside the metric system, though it never caught on widely and was abandoned within a couple of years.
- Is decimal time the same as "internet time" or Swatch beats?
- No — this is the classic 10-hour French Revolutionary scheme. Other decimal-time proposals (such as Swatch Internet Time, which divides the day into 1000 ".beats") use different divisions.