The perpetual calendar stands out in my eyes as Audemars Piguet’s finest complication. The manufacture has of course made countless fine pieces of haute horlogerie over the years, but for me the perpetual calendar brings out its very best. Sébastian Vivas, Audemars Piguet’s Heritage and Museum Director, agrees and says that “perpetual calendars have marked the history of Audemars Piguet since 1875.” That’s why they are such an important part of the Vallée de Joux landscape, with each new perpetual calendar adding more horological depth to the collection.

Audemars Piguet Royal Oak Selfwinding Perpetual Calendar (©Revolution)

When I first saw the Caliber 7138-equipped Royal Oak in Le Brassus at the beginning of the year, I was impressed by the concept. The movement really came to life in the demonstrations by Lucas Raggi, AP’s Chief Industrial Officer, and his team. They were genuinely proud of their achievement with the 7138. As I watched, the movement revealed its particular rhythm: every jump, every click, every coupling occurred with the clarity and precision of a David Gilmour solo, where nothing is superfluous, nothing is missing, and every note — or in this case, every tooth, every cam — falls exactly where it should. And, for the first time, adjusting a perpetual
calendar is a joy.

The Caliber 7138 (©Revolution)

Based on the architecture of the Caliber 7121, the 7138 — 4.1mm high and 29.6mm in diameter — allows all the time and perpetual calendar indications (day, date, month, leap year and astronomical moonphase) to be adjusted via the crown. This means an unprecedented ease of operation and addresses one of the perpetual calendar’s long-standing drawbacks: a reliance on awkward, risk-prone pushers that demand pinpoint accuracy and can damage both the mechanism and the case if mishandled. With the 7138, such horror stories are a thing of the past.

The crown is the command center of the watch, operating in clearly defined positions: Position 1 — manual winding; Position 2 — quick crown adjustment of the date (clockwise), and the year and month (counter-clockwise), with the date protected by a safety system; Position 3 — time adjustment. And, as a feat of ingenuity, a fourth functional position emerges when returning from Position 3 to 2: here, the day and week (clockwise) and moonphase (counter-clockwise) are adjusted. All of this is protected by five patents, including the internal safeguards to prevent mis-setting or damage, the ultra-thin integrated architecture, and the mechanism that allows bidirectional adjustment of the calendar.

Details on the dial (©Revolution)

As a result, the new Royal Oak models feature cases without side perforations, a 55-hour power reserve, and calendar accuracy until the year 2100. In the past a good watch winder was indispensable for an automatic perpetual calendar. Today, with Audemars Piguet’s 7138 movement, it is almost tempting to let the mainspring run down to enjoy the pleasure of winding and setting it. This step-change establishes it as Best Calendar Watch of 2025.