Decimal Clock

Common questions

What is decimal time?

French Republican decimal time, associated with the French Revolution, splits a day into 10 hours, each with 100 minutes of 100 seconds. That is 100,000 decimal seconds instead of 86,400 ordinary seconds. One decimal second is exactly 0.864 of an ordinary second, and one decimal hour lasts 2 hours 24 minutes. This clock demonstrates that scale alongside ordinary decimal hours.

Why does a decimal clock show 5:00:00 at noon?

Noon is halfway through the day, so it is halfway through ten decimal hours. Midnight starts at 0:00:00, 06:00 reads 2:50:00, and 18:00 reads 7:50:00. At 23:59:59 the reading is 9:99:98; the clock returns to zero at midnight. The landmark rows show midnight and noon on the scale you select.

How do you convert clock time to decimal time?

For the ten-hour scale, count ordinary seconds since midnight and divide by 0.864. At 18:00 there are 64,800 ordinary seconds, giving 75,000 decimal seconds, or 7:50:00. The ten-hour reading truncates to a whole decimal second. Ordinary decimal hours instead use hours + minutes/60 + seconds/3600, rounded here to three decimal places; one step in that display is 3.6 ordinary seconds.

Is 18.5 hours the same as 18:50?

No. The fraction in 18.5 is half an ordinary hour, so it means 18:30. That time is shown as 18.500 h on the 24 h scale and 7:70:83 on the ten-hour scale. The Scale control changes which reading is large.

Does it use my time zone, and what happens when the clocks change?

The live reading starts from your device clock and uses your browser's time zone database for the selected zone and date. Decimal time follows the wall clock, so it jumps or repeats when that clock changes. A day with a one-hour change lasts 23 or 25 elapsed hours; a half-hour change lasts 23.5 or 24.5. The note identifies the change for the date shown and flags a typed time within a skipped or repeated period.

Can I convert a particular time rather than watch the clock?

Yes. Choose Set time and enter an ordinary time such as 18:31:40, 18:31, 1831, 183140, 6:31:40 pm, noon or midnight. The box accepts a time of day from 00:00:00 through 23:59:59, not a duration or an hours-worked total. It rejects invalid hours, minutes and seconds with a specific message. The date used for time zone rules remains the current date in the chosen zone.

Can I enter decimal hours or ten-hour decimal time?

The input takes ordinary clock time. It does not accept a decimal-hour number or a French decimal reading as input. For example, entering 18.5 produces an explanation instead of a converted result. The conversion chart is a lookup reference; the clock does not calculate shifts, subtract start and end times, or total a timesheet.

How do time-clock minutes become decimal hours?

Divide the minute part by 60, then add the whole hours. Fifteen minutes is 0.250 hours, thirty is 0.500, and forty-five is 0.750. The chart includes every whole minute from 00 through 59 in its first-hour rows. For 08:45, adding 8 to 0.750 gives 8.750 hours. These fractions use ordinary 60-minute hours.

Are my entries uploaded?

The time conversion runs in this page without uploading your typed time or chosen zone. The clock remembers its settings in this browser after you change a control. Copy places a labelled reading on your clipboard if the browser permits it; it does not download a file.