An Introduction To Complications: The Perpetual Calendar

The perpetual calendar is one of the most useful and romantic complications in all of horology. You may have noticed that many watches have some sort of date indication, usually in the form of a small window in the dial displaying the day of the month.

Some even have a day of the week display as well. The perpetual calendar has both of these and more, plus it only needs to be adjusted once a century. Yes, we said once a century.

Editor's note: This is part four in a series of introductory pieces on watches from our friends at Hodinkee. You can read part one here, part two here and part three here.

With the perpetual calendar you can track the date, day of the week, month, year, leap year, and sometimes even the century and millennium. Thanks to the varying lengths of the months and those pesky leap years, a perpetual calendar watch has a plethora of gears that turn multiple times per second to only once every four years or more. As such, this is a watch that, assuming you keep it wound (good time to invest in a winder), will not require any adjustments until the year 2100 at the earliest - leap years are skipped at the turn of a century, so the normal mechanical calculations require a tiny push forward at the end of February.

Perpetual calendars are typically elegant and dressy, which you might attribute to their usually high price tags, and the perpetual calendar chronographs from Patek Philippe are some of the most sought after watches of all time. That said, Jaeger-LeCoultre has just released an elegant perpetual calendar in stainless steel, one of the few dressy perpetuals to come in under $US30,000, and IWC has produced a number of interesting perpetuals over the years, including the Da Vinci, the Portuguese, and the Ingenieur Digital Date-Month.

Because each watch takes weeks or months to make, and only highly skilled watchmakers can even begin to work on them, perpetual calendars do come at a cost. While it may keep them off the wrists of most watch enthusiasts, there are few complications that get true watch nerds so excited.

HODINKEE is a robust online magazine featuring in-depth reviews, critiques and reports on watches of a particularly high calibre.