I’ve gone off-topic again to talk about something that fascinates me. I’m not an expert and you shouldn’t use this journal post for anything important or even to set your clocks by…

For some reason, I find date and time fascinating.  I’m not an expert in any of this, but a lot of what we do online relies on the time on our devices being correct – especially at the moment, when it’s getting harder to keep track of what day of the week it is.  So I thought it would be interesting to talk through some ways of displaying and getting the current Date and Time, along with a clock that the founder of Amazon is building…

I’m picking the date and time of 25th December 2019 13:45 London GMT/UTC for this article.

And I’ll run through a few ways to display this date as well as taking a look at some interesting quirks…

Displaying Date/Time

There are lots of ways to display the date and time. Let’s take a look…

Some pretty standard ways you might see everywhere:

  • 25th December 2019 1.45pm
  • 25-Dec-19
  • 25-Dec-2019
  • 25/12/19

Train Tickets: 25-DMC-19

For some reason that I can’t quite work out, they don’t use DEC as the short code for December?!  One internet user suggested that “They don’t want to show favouritism in the great Ant vs Dec debate” which works for me!

ISO 8601: 2019-12-25T13:45:00

ISO stands for International Organization for StandardizationThis method of denoting time is supposed to be an international standard, to get rid of confusion between different countries about which number is the day and which is the month.  So this format goes YYYY-MM-DD.  It’s also handy for clearing up confusion between different countries’ methods of describing time.  For example, saying “See you at half four” means half past four in the UK – but in Germany, “half four” would mean half an hour before four o’clock, i.e. 3:30.  Which could lead to embarrassing misunderstandings!

The USA format: 12/25/19 13:45:00

For reasons best known to themselves (to annoy the rest of the world, perhaps), in the US they use the format MM/DD/YYYY.  That’s why in a lot of American films and TV programmes, you’ll hear people say “October 3rd” rather than the 3rd of October.

Epoch: 1577281500

This one’s a bit of a techy one, sorry… Sometimes called UNIX time or Linux times, Epoch is the number of seconds since January 1, 1970 (midnight UTC/GMT).  This system was created by computer programmers to help them make complex time calculations. I’m not sure why they picked that particular date to start from, but they did… (and for those counting, this number doesn’t include leap seconds!)

Not to be confused with the cute fuzzy ‘bears’ from Star Wars known as Ewoks.

Swatch Beats: 25-12-2019 @615

Literally invented by the Swedish company Swatch as part of a marketing campaign to launch their line of “Beats” watches. It split the day into a 100 Beats starting at… well, to be honest, I read the Wikipedia page and I’m still confused. It never really took off, but you can see the current @Beats time here http://www.swatchclock.com/

Roman numerals: XXV.XII.MMXIX (DD.MM.YYYY)

In 1976, the BBC began showing the production dates of their programmes in Roman numerals at the end of the credits. I’m not sure why – if anyone has any ideas, feel free to get in touch!

Ways to get the time/odd things:

Devices like smartphones and computers are pretty good at knowing the time – but how do they know?  It’s not as if they can look at a clock on the wall! So here are some ways that devices get the current date/time:


NTP stands for Network Time Protocol – this is the way most internet-connected devices get the time. Normally a device like your phone will connect to an NTP server that’s linked to an atomic clock, to make sure the time it gives is precise.  This server usually gives your device the date/time in GMT, then your device converts this to your local time.

Rough time

This is a new-ish secure internet protocol like NTP, but the time you get from the service is within ~10 seconds of real-time. The intended use of this is when you need a time that is secure and accountable, but the trade off is that it’s not 100% accurate.

Amazon’s “clock in a mountain”

Fancy a hike into the mountains of west Texas?  Jeff Bezos, founder of shopping giant Amazon, has been investing in a project to build a clock that keeps accurate time over a whopping 10,000 years.  The Clock of the Long Now will tick once a year, the ‘century’ hand will move once every hundred years, and the cuckoo will come out on the millennium.  Sounds a bit like something out of a Douglas Adams book (what happens in year 42, I wonder?) but it’s certainly an interesting idea.

Leap second

Leap seconds are similar to leap years, only on a much smaller scale.  So a leap second is a one-second adjustment that gets applied to UTC every so often, to accommodate the gradual slowing of the earth’s rotation.  To account for this occasional extra second, some time services just jump a second at the end of a leap year, whereas some spread out the second over a few hours, by adding a millisecond here and there.

Radio-controlled clock time

The clocks pick up a radio signal being transmitted and set their time accordingly.  This isn’t like a regular radio station though – there’s no music or DJ, no adverts (thankfully) and all that’s being broadcast is the time, over and over.  In the UK, this station is called MSF.  Some radio-controlled clocks pick up the signal once a day, some do it every few hours.


It’s more or less the same thing, but there is a technical difference: https://www.timeanddate.com/time/gmt-utc-time.html says “Greenwich Mean Time (GMT) is often interchanged or confused with Coordinated Universal Time (UTC). But GMT is a time zone and UTC is a time standard.

Time on the international space station:

In space, the time is always kept in UTC.

Sundials, hourglasses

How sundials cope with leap seconds I don’t know. Maybe the people who set the time come and change them all by hand? (Again, if you know anything about this, feel free to get in touch!)

Atomic clocks

Atomic clocks are the most accurate clocks that we have – so far, anyway.  They use signals from the electrons in atoms (which vibrate at very regular frequencies) to keep the time correctly. A bit like the pendulum in a grandfather clock, only much more precise.


As you can see, there are plenty of ways to display the date and time. Here’s my simple guide:

  • If you’re writing something like an invoice* or letter, I would use “25th December 2019”, as it’s a bit more formal.
  • When you’re using the date for something you need to sort, like file names for Backups of files, or putting dates in a spreadsheet, use “2019-12-25”.

My least favourite is anything that can be confused like 12/25/19. Which in this case is fine, but imagine if the date was 12/11/19 – you could be out by a whole month if you’re using a different date format! So it’s definitely worth thinking about…

Mike =) 

*Although if you have had an invoice in the post from us recently you’ll notice we sometimes use 25/12/19 and sometimes 25 December 2019. It’s on my list of things to fix!

Why We Should Reform The Calendar – 13 Months Instead of 12