I like the concept behind Swatch Internet Time. It seems fun yet kitsch. It has no real time zone or daylight saving time issues. It is a nice idea, too, as there is a compact notation. However, it has three potential issues: there’s no handling for fractions of a beat, it’s based on where Swatch is located (Biel, Switzerland), and there is no standard for calendar day notation. So, I’ve taken it upon myself to extend the standard to Universal Decimal Time (UDT) to address these perceived issues.

First, what is the calculation. It’s simple. Take the hour and multiply that by 3600. Next, add this to 60 times the minute. Next, add that to seconds. Finally, divide the total by 86.4. In the Swatch Internet Time, you round down. This is your beat. However, UDT will allow for fractions of a beat up to 2 decimal places.

Next, the time zone used by UDT is important. It seems realistic to me that it will use UTC for a variety of reasons, including it’s “standard”, no daylight saving time, and the leap seconds appear to be accounted. This means the hour, minute, and seconds used i the calculation are with reference to UTC and not UTC+1 like Swatch Internet Time.

Next, the date is included. This is again with reference to UTC and uses the international “YYYY.DayPercentInYear” format. The DayPercentInYear is the percent of days into the year, such as 20%. However, for the UDT format, it will drop the percent sign.

Finally, putting it all together. I’ve chosen to use the Unicode symbol for white hour glass, as it seems to show up better on pages, as leading character. The calendar date is separated from the beat with an “@” symbol like in Swatch Internet Time. A sample, as of this writing, for a string representing UDT would be “⧖2024.20@435.69”.

Enjoy!