Is your Annual Calendar
the real deal?
The Patek Philippe Annual Calendar is one of horology's most iconic complications, requiring just one correction per year. Its high value and prestige make it a prime target for sophisticated counterfeits. Here's how to tell the difference.
How to authenticate an Annual Calendar
Calendar Aperture Layout & Font
The Annual Calendar features three aperture windows displaying day, date, and month. On genuine models like the Ref. 5205G and 5905R, these windows use a specific proprietary font with precise sizing and spacing. The apertures are laser-cut with perfectly sharp edges and sit in exact symmetrical positions. Counterfeits often have slightly different fonts, uneven spacing between apertures, or rounded window edges.
Moonphase Disc Detail
On models equipped with a moonphase complication, the disc features a hand-painted or intricately stamped moon against a deep blue or black sky with individually applied stars. Genuine Patek moonphase discs have exceptional detail and depth, with crisp star points and a perfectly round moon face. Counterfeits typically have flat, poorly painted moons with blurry stars and uneven coloring.
Case Finishing & Hand-Beveled Lugs
Patek Philippe cases are finished to the highest standards in the industry. The lugs are hand-beveled with mirror-polished chamfers that create crisp, defined edges transitioning between polished and satin-finished surfaces. Under magnification, genuine Patek cases show no machining marks, tool traces, or waviness in the polished surfaces. Counterfeits cannot replicate this level of hand-finishing and often show rounded edges or visible machining lines.
Caliber 324 S QA LU Through Case Back
The Annual Calendar houses the Caliber 324 S QA LU, visible through a sapphire display case back. The movement features a 21K gold central rotor with the Calatrava cross, Côtes de Genève striping, hand-beveled bridges, and the Geneva Seal. The finishing should be flawless under magnification. Counterfeit movements lack this level of decoration and may use a generic base movement with cosmetic modifications.
Calatrava Cross on Crown
The winding crown features the iconic Calatrava cross emblem, Patek Philippe's trademark. On genuine watches, this emblem is deeply embossed with sharp, precise edges and perfectly symmetrical proportions. The crown itself should have a satin finish with polished edges. On counterfeits, the Calatrava cross is often shallow, poorly defined, asymmetrical, or has rounded points instead of sharp ones.
Geneva Seal
Every Patek Philippe movement bears the Geneva Seal (Poinçon de Genève), a hallmark of quality guaranteeing the movement meets strict finishing and accuracy standards set by the Canton of Geneva. The seal should be visible on the movement through the case back. It is engraved with extreme precision and cannot be replicated by counterfeiters. A missing or poorly executed Geneva Seal is an immediate red flag.
Annual Calendar counterfeit warning signs
Misaligned Calendar Apertures
On genuine Annual Calendars, the three aperture windows (day, date, month) are positioned with absolute precision and perfect symmetry. The text within each window should be perfectly centered. If the apertures appear uneven, are different sizes, or the text sits off-center within the windows, it is almost certainly a counterfeit. Even sub-millimeter misalignment is unacceptable on a genuine Patek Philippe.
Poor Moonphase Painting
The moonphase disc on a genuine Annual Calendar is a miniature work of art. If the moon face looks flat, the stars are unevenly spaced or blurry, or the sky background has visible brushstrokes or uneven coloring, the watch is likely fake. Genuine Patek moonphase discs have depth and luminosity that counterfeits cannot achieve.
Wrong Date Font
Patek Philippe uses a proprietary typeface for the day, date, and month displays within the aperture windows. Counterfeits frequently use generic fonts that are similar but not identical. Pay close attention to the numeral style, letter weight, kerning, and overall character proportions. Even slight differences from the reference font indicate a fake.
Missing Geneva Seal on Movement
Every genuine Patek Philippe movement bears the Geneva Seal. If the movement visible through the display case back does not show the Geneva Seal, or shows a poorly engraved imitation of it, the watch is counterfeit. The seal should be crisp, deeply engraved, and positioned correctly on the movement plate. Additionally, the overall movement finishing should be flawless with no visible tool marks.
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Frequently asked questions
What is the difference between an annual calendar and a perpetual calendar?
An annual calendar automatically accounts for months with 30 and 31 days but does not account for February's shorter length. It requires one manual correction per year at the end of February. A perpetual calendar accounts for all month lengths, including February and leap years, requiring no correction until the year 2100. Annual calendars are less complex and typically more affordable than perpetual calendars.
How many corrections does a Patek Philippe Annual Calendar need per year?
The Patek Philippe Annual Calendar requires just one manual correction per year, at the end of February. On March 1st, you need to advance the date from February 28 (or 29 in a leap year) to March 1. For the remaining 11 months, the calendar automatically distinguishes between 30-day and 31-day months without any intervention.
What is the difference between the Ref. 5205 and Ref. 5905?
The Ref. 5205 is a time-only annual calendar with hours, minutes, seconds, and the day, date, month, and moonphase displays. The Ref. 5905 combines the annual calendar complication with a chronograph function, adding start/stop/reset pushers on the case side and a subdial for elapsed time. The 5905 is a larger, more complex watch with a higher price point due to the additional chronograph mechanism.