Clocks are everywhere, and almost everybody wears a watch. On each computer screen there is a clock ticking the seconds, minutes and hours away. Hundreds of times each day we want to know what time it is.

Why don’t we use the metric system to measure time? The metric system is used (in most civilized countries) for measuring all kinds of things, including length, area, volume, weight or mass, and even currency. We are used to measuring all these in a base 10 system. A kilometer is thousand meter, a centimeter is 1/100 of a meter, a liter equals 1000 milliliters, 1000 grams is a kilogram, etc.

But time is measured in a different way. Twenty four hours in a day, sixty minutes in an hour, sixty seconds in a minute, and yes, when we measure in fractions of a second we suddenly do it the metric way and we talk about milliseconds. Isn’t it time that we also use the metric system for measuring time? (people who think in ounces, inches, gallons and miles don’t have to read on)

Let’s explore how it would be to use Metric Time. Days would be the same, because the length of a day depends on the rotation of the earth. But we will have to change the length of hours, minutes, and seconds.

How we do it now | The metric system |
---|---|

24 hours per day | 10 hours per day |

60 minutes per hour | 100 minutes per hour |

1,440 minutes per day | 1,000 minutes per day |

60 seconds per minute | 100 seconds per minute |

3,600 seconds per hour | 10,000 seconds per hour |

86,400 seconds per day | 100,000 seconds per day |

What does this mean for the length of hours, minutes and seconds? A second will get slightly shorter. Minutes will be a bit longer. And hours will take much longer. Metric hours are 2.4 times the hours as we know them now.

## Convert "old" time to Metric time

1 metric second | = | 0.864 "old" second | ||

1 metric minute | = | 1.44 "old" minute | ||

1 metric hour | = | 2.4 "old" hour |

### What does it mean in practice?

There is no AM and PM anymore because we have only 10 hours in a day. Noon is at 5:00. If you are used to work from 9:00 AM to 5:00 PM, the metric clock means that you have to start at 3:75 (i.e. quarter to four) and by 7:08 you can call it a day.

### Breaking world records

The world record ice skating on 5,000 meter is now 6 minutes and 3.32 seconds (Sven Kramer, November 2007). In the metric system this record would be 4 minutes and 20.51 seconds. This looks faster but it is exactly the same. But breaking the record should be easier because metric seconds (and thus hundredths of a second) are a bit shorter.

### Cooper test

If you run a Cooper test with a metric watch, you will have to run 8 minutes and 33 second (8.33 minutes).

### Abandon hours, minutes and seconds

A proper metric system for time would probably drop the use of hours, minutes, and seconds. The standard unit would be the day, and the metric hours would be called decidays, the minutes would be millidays, and a metric second would be 10 microdays.

### Or keep the seconds

If we keep seconds as the basis for metric time, then a minute will be called decasecond, an hour will be 10 kiloseconds, and a day is 100 kiloseconds.

### Expected problems

There are probably farmers who think that with metric time the cows would give less milk.

## What time is it now in metric time?

Here is a digital clock converting standard time to decimal time:

Standard time:

Decimal time:

## Tip

Keep this browser tab open! The browser tab will show you the current decimal time.

See also this analog decimal clock.

Gary HardingI think we should still have 20 hours per day. 10 day hours and 10 night hours. The day hours start at the old 6am and go to 6pm. The night hours start at the old 6pm and go to 6am.

Therefore your metric clock would be ie: 3:20 night clock or 2:50 day clock.

HeinIt’s an idea. Maybe I will make one like that some day.

I recently made an analogue version of the metric clock. See here: https://bijlmakers.com/decimal-clock/

Brantonhow about a 100 hour day

each hour 100 minutes

each minute 100 seconds

1,000,000 seconds in a day

(each hour is 14 minutes 24 seconds regular time)

here is a link to an example I made:

HeinYes, it’s a possibility. Good idea.

DanTotally disagree. 20 hours a day is not metric anymore than 24 is. 10 hours a day.

However I also believe you can’t use the standard day as a basis for metric timekeeping. It just doesn’t work. 365 “metric” days in a year instead of a thousand isn’t metric either. I believe one would have to use the year as the foundation of a metric timekeeping system.

HeinI think timekeeping (a clock) is to look at the moment within a day. A clock divides the day in units.

When you talk about 1000 days in a year, you start thinking about a metric calendar instead of a metric clock. But that’s hard to do; you can’t force the earth to rotate 1000 times in a year as it will do only 365.25

We cannot decide how many days there are in a year. But we can decide how many hours in a day.

Rajneesh ChellapillaThat m les more sense a 20 hour day is more intuitive. 20 hour day, define 1/50 hours as a minute, 1/100 minutes as a second and it still works out as 100000 metric seconds in a day.

Ben R.I honestly can’t see people switching over to metric time when pretty much the entire world uses standard time, It wouldn’t just be farmers. The logistical nightmare that would be switching the entire world economy, textbooks, calendars, history, scientific calculations, etc would be catastrophic. I use metric pretty often for an American and even I can’t see the point of changing the entire time scale when standard time (60 seconds in an hour, 60 seconds in a minute, etc) is already universal among everyone.

Mike T.Why base metric time on earths rotation? If we are eventually going to be interplanetary beings, shouldn’t we base it on a more universal (the universe, not just our solar system) standard. Maybe, for example, the half life of a carbon atom, or some other scientific standard that is constant throughout the universe as we know it. I think even the speed of light can be influenced by different factors so that’s out.

HeinProbably because you want to wake up at the same (earth) time every morning.

boredOur measurement of time would have to change, currently 864000 milliseconds in 1 day. 1 millisecond would have to become either 864 or 0.864 milliseconds long. a millisecond being the current metric measurement. after that is redefined then we can begin to convert into metric.

The time of day is variable by several hundred microseconds, ignoring that. Using 1 Day as the Time Unit we would then divide time into deciDay = 2.4 Hours. CentiDay = 14.4 current minutes, milliDay = 864 milliseconds. Or 1K Time Unit = 1 Day and 1 milli Time Unit = .864 milliseconds.

JohnThe probably with metric time is that you eventually run up against natural time somewhere which doesn’t lend itself to the metric system. With this system, we would still have 12 months and 365 days per year except on leap years. This conversion could only apply to hours per day, minutes per hour, and second per minute. That’s probably not worth the trouble.

AlexThis would have been so much easier to change before industrialization, earlier be easier. Now all the machines, electronics, formula are all based on this old clock system, it’s impossible for the entire human race to change.

Same for American’s imperial system, with every going day it’s getting more and more expensive to switch so I see the USA will always be on that old system.

AlexFor example, driving speed will be in a different numeric value and it’ll take years cities to post new signs, and even longer for people to adapt.

The computers we use will need brand new programming codes, hardware manufactures will need to change their firmware code too.

Warren van NiekerkI love the idea, we should already start using it. It will really confuse people when they ask for the time 🙂

How will it accommodate leap years and leap seconds? https://en.wikipedia.org/wiki/Leap_second