When it comes to measuring time, the metric prefixes are commonly used for periods less than one second long, but longer than that it becomes the mess that is minutes, hours, days and beyond.

But have you ever wondered what the proper, SI, power-of-1000 equivalences are? Here’s are some handy conversions.

SI unit Rough equivalence
kilosecond 16.67 minutes (quarter of an hour)
megasecond 11.57 days (third of a month)
gigasecond 31.71 years (third of a century)
terasecond 31.71 millennia (what did you expect?)
petasecond 31.71 million years (eighth of a galactic year)
exasecond 31.71 billion years (2.3 times the age of the universe)

And in reverse:

Weird unit Exact SI equivalence
minute 60 seconds
hour 3.6 kiloseconds
day 86.4 kiloseconds
week 604.8 kiloseconds
month (30d) 2.592 megaseconds
year (365d) 31.536 megaseconds
decade 315.36 megaseconds
century 3.1536 gigaseconds
millennium 31.536 gigaseconds

Some fun, suspiciously astronomically-related facts:

  • Earth sidereal day: 86.164 kiloseconds
  • Neptunian year: 5.197 gigaseconds
  • Galactic year: approx. 7.25 petaseconds
  • Age of the Universe: 435.17 petaseconds

These values work identically for light-years, e.g. 1 light-year = 31.536 megalight-seconds.

Now go call the Millenium Falcon the “Gigasecond Falcon.” Go on, I dare you.