timetoten.

A working replica of the decimal clock decreed by France in 1793. Ten hours, one hundred minutes, one hundred seconds — to a day.

Editionv.04 · live
Position
Offset
Status◉ Updating · 1 s
0 : 00 : 00
Day so far 0.000
Standard, now
00:00:00
local
Next dec. hour in
00:00
standard mm:ss
What you're looking at →
10
hours per day
instead of 24
100
minutes per hour
instead of 60
100
seconds per minute
instead of 60
02 / Convert Drag, or type
Standard
HH : MM : SS
Decimal
H : MM : SS
00:00 / 0:00 06:00 / 2:50 12:00 / 5:00 18:00 / 7:50 24:00 / 10:00
Drag the scrubber, or type into either field. 50.00% of day
03 / Calibration 3 units · 3 things you already know

What does it feel like?

A decimal hour is a long film.

— 2 h 24 min standard

A decimal minute is a long red light.

— 1 min 26 s standard

A decimal second is a heartbeat.

04 / Cheat sheet Nine moments of the day
#StandardDecimalDay %Notes
0000:00:000:00:000.0%Midnight
0102:24:001:00:0010.0%1 decimal hour
0206:00:002:50:0025.0%Quarter day
0309:36:004:00:0040.0%4 decimal hours
0412:00:005:00:0050.0%Noon — midi décimal
0514:24:006:00:0060.0%6 decimal hours
0618:00:007:50:0075.0%Three-quarter day
0721:36:009:00:0090.0%9 decimal hours
0824:00:0010:00:00100.0%End of day
05 / Questions
Q.01

What is a decimal clock?

A decimal clock divides the day into 10 hours instead of 24. Each hour holds 100 decimal minutes; each minute holds 100 decimal seconds. The day still lasts exactly 24 standard hours — it is only the counting that changes. One decimal hour is 2 hours 24 minutes of standard time. One decimal minute is 1 minute 26.4 seconds.

Q.02

Was the decimal clock ever really used?

Yes. The French National Convention legislated decimal time on 5 October 1793. It became mandatory on 22 September 1794 and was officially suspended on 7 April 1795 — though the great clock on the Tuileries palace continued to display decimal time on its second face until at least 1801. Watchmakers produced dual-dial pieces during the transition.

Q.03

How do I convert standard time to decimal time?

Multiply the number of standard seconds since midnight by 100,000 / 86,400 ≈ 1.1574. Then split the result into decimal hours, minutes and seconds. Or just type a time into the converter above.

Q.04

What is the difference between decimal time and metric time?

They are usually treated as synonyms in modern usage — a base-10 division of the day. "Decimal time" is the older, France-specific term; "metric time" is the more common contemporary phrasing among hobbyists who advocate it as a natural extension of the SI system.

Q.05

Why is it abandoned if it is more logical?

Switching costs. Every clock, every printed schedule, every contract referenced standard time. Decimal time required retraining the entire population and re-tooling every workshop in France during a period of war. The Revolutionary calendar (with 10-day weeks) suffered the same fate and for the same reason: change is easy to legislate and hard to live.

A small monument
to a bigger idea.

timetoten is a working replica of the decimal clock decreed by the French Republic in 1793. The decree was repealed eighteen months later. The clock above the Tuileries kept running on its second dial until 1801. This page is the same clock, rebuilt in HTML — accurate to the standard second, recomputed in your browser, and committed to nothing else.

Built by
Someone curious
Runs on
Your local time
Tracks
Nothing