Know your Calendar Complications

Tudor Prince Oysterdate

Know your Calendar Complications

To put it simply, watch complications are functions beyond the standard telling of time. This includes the beautiful Power Reserve Complication. A handy function that indicates how much stored energy is left in your mechanical watch so you’ll know when to wind it before it’s too late.

Today we’re going to dive into another series of useful functions: Calendar Complications.

Montre Rolex - Oyster Perpetual Datejust - Sigma Dial - 1960/1970


When you’re writing a check, making an appointment, or simply checking to see if sales are still going on at your favorite store you’ll probably need to ask the person next to you “What’s today’s date?” Of course you can search through your bag or pockets and take out your mobile phone to check, but wouldn’t it be easier and so much more stylish with a simple turn of the wrist?

Let’s begin with the simplest calendar complication: the Date.

Date Window

This is the most common type of date display. A digital date is indicated through an opening or “window” on the dial, often at 3 o’clock.

A tiny disk marked with the numbers 1 through 31 around has been placed behind the dial. For months with less than 31 days, the watch’s date will need to be adjusted manually at the end of the month.

Rolex Oyster Perpetual Datejust avec cadran “Sigma”

Big Date

As you may have figured out from its name, this format allows a much larger, and thus more legible, view of the date. Often you’ll have a pair of side-by-side windows that together form a digital date: the left window displaying numbers from 0 to 3, the right one with 0 through 9.

The Big Date can be commonly found at noon or 6 o’clock.

A. Lange & Söhne Datograph Up Down

Montre Oris Big Crown Pointer Date Anniversaire Cadran Vert

Pointer Date

This analog date display is created by a date wheel that usually runs around the outer rim of the dial, and, as its name suggests, a center hand that points to the date. This disposition is often referred to as the “Bankers’ Dial.”

Oris Big Crown

Subsidiary Date

Here the date is indicated via a sub-dial commonly found at 6 o’clock, and in association with other complications.

Patek Philippe 5320G

Longines Conquest Day Date


The Day-Date complication is a step up from the Date complication in that it also presents the day of the week in addition to the date of the month.

Common layouts include a window at noon showing the day of the week, and the date 1 through 31 at 3 o’clock. Another type of disposition is side-by-side windows at 3 o’clock with the day of the week reduced to a 3-letter abbreviation.

As with the Date complication, the wearer must manually adjust his watch for months with less than 31 days.

Longines Conquest “Day Date”

difor triple calendrier valjoux 72c or

Triple Calendar

Also called a “Complete Calendar,” this complication adds a specific month to the Day-Date complication.

Various dial layouts are possible. For example, a double window at noon displaying the day and the month while a central hand points to the date. Another popular disposition is a trio of sub-dials presenting the month, day, and date.

Just like the Day-Date complication, the watch will sometimes need adjustment at the end of month.

Difor Triple Calendrier 

Annual Calendar

What’s left to add to the Triple Calendar? Taking account of the year of course. Which is exactly what the Annual Calendar complication does.

It provides an accurate calendar for all non-leap years and doesn’t need any correcting whatsoever at the end of the month. It does, however, need to be adjusted at the end of each February, otherwise the watch will go to February 31st before turning March 1st.

It does, however, need to be adjusted at the end of each February, otherwise the watch will go to February 31st before turning March 1st.

Blancpain Villeret Quantième Annuel

Perpetual Calendar

Although the Perpetual Calendar complication deserves an article all by itself, I’m keeping it brief for our purpose today.

From the watchmaker’s point of view, this is the most complex calendar feature to design and craft in a watch.

For us, the Perpetual Calendar complication is perhaps one of the most useful complications that exist. Not only does it show everything an Annual Calendar shows, but it takes into account the leap years. This means there’s no need to adjust anything at the end of any month, any year. The complication handles all of that. Amazing but true!

The function does need to be corrected, however, once a century when the leap year is ignored. That’s right, once every 100 years. More than a demonstration of a watchmaker’s excellence or know-how, the Perpetual Calendar and the other Calendar complications mentioned above are pretty damn useful for everyday life.

Glashütte Original Excellence Senator Quantième Perpetuel

Porte-Cartes en Cuir Pigskin Noir
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