Astronomical & visual time
Decimal & Swatch time
Two experiments in reinventing the clock, both ticking live: the metric decimal time of revolutionary France, and Swatch Internet Time — 1000 .beats a day, the same number everywhere on Earth.
Decimal time divides the day into ten hours of a hundred minutes each — a relic of the French Revolution. Swatch .beats slice the day into 1000 units on a single worldwide clock, with no time zones at all.
How to use the decimal & swatch time
Read French Revolutionary time
The day is divided into 10 hours of 100 minutes, each of 100 seconds. Decimal noon is 5:00:00, and a decimal hour is 2 hours 24 minutes of ordinary time.
Read Swatch Internet Time
The day is 1000 .beats, each 86.4 seconds. There are no zones at all — @500 is the same instant everywhere on Earth.
Compare with your clock
All three run side by side against the same moment, which is the quickest way to build intuition for the conversions.
Note the reference meridian
Swatch time is computed from Biel Meantime, equal to UTC+1, which is why @000 is midnight in Switzerland rather than at Greenwich.
Two attempts to replace the 24-hour day
Revolutionary France decimalised almost everything successfully — the metre, the gram, the litre are all still with us — and then tried the same with time. From 1794 the official day had 10 hours of 100 minutes of 100 seconds. It lasted about seventeen months. Metric length required new rulers; metric time required every clock in the country to be replaced, and the arithmetic advantage was not worth it.
Swatch Internet Time, launched in 1998, attacked a different problem: time zones. Dividing the day into 1000 .beats with no zones at all meant an online meeting could be called for @500 and everyone, everywhere, would arrive at the same moment. For a brief period it appeared in ICQ, on Swatch watches, and in one Ericsson phone.
It failed for an instructive reason. Removing zones does not remove the underlying problem — people still need to know whether @500 is a civil hour where the other person is. Zones are not an accident of history; they encode the relationship between clock time and daylight, which is the thing anyone scheduling actually cares about. Coordination in UTC solved the same problem without asking anyone to relearn the clock.
Both survive as curiosities worth understanding, because both illuminate why the awkward, historically contingent 24-hour system persists: it is tied to the sun, and everything that has tried to replace it has quietly dropped that connection.
When you'd reach for it
Curiosity
See what time it is right now in two systems that tried to replace the clock.
Teaching history
A concrete way into the French Revolution's metrication programme.
Design and fiction
A plausible alternative timekeeping system for a game or a story.
Nineties nostalgia
Swatch .beats were briefly everywhere online.
Thinking about zones
A zoneless system makes clear what zones are actually for.
Conversation piece
A clock that makes people ask what they are looking at.
Questions & answers
- What is decimal time?
- A system from revolutionary France that splits the day into 10 hours, each of 100 minutes, each of 100 seconds — a fully metric clock. It was briefly official in the 1790s.
- What is Swatch Internet Time?
- A 1998 idea dividing the day into 1000 “.beats”, based on Biel Mean Time (UTC+1) with no time zones — the same beat number worldwide, so @500 is midday BMT everywhere.
- Do these match my normal clock?
- They represent the same instant, just counted differently. Decimal time follows your local day; Swatch beats are the same for everyone on Earth.