Short answer

A replica Audemars Piguet Royal Oak Perpetual Calendar 26574 is a copy of the 41mm steel or gold reference. No copy of this watch carries a true perpetual calendar. On most copies the month disc, the leap year window and the date run off a standard gear train, so the display loses the real date after a few months. Street price runs from about $400 to $900.

What the real 26574 is

Audemars Piguet builds the 26574 with a 41mm case, a Grande Tapisserie dial, and caliber 5134. Caliber 5134 sits on the 2120 base, an ultra-thin automatic that beats at 2.75 Hz (19,800 vph) with a 40-hour power reserve. The dial shows day, date, month, leap year, moon phase and week of year. Case thickness is about 9.5mm. Retail sits in the mid five figures in USD, and steel examples trade above retail on the secondhand market.

Where copies differ

  • Thickness. Most cases measure 10.5mm to 11mm, or 1mm to 1.5mm over the real watch.
  • Calendar logic. Month and leap year discs move with the date train or a pusher. The watch does not know February has 28 days.
  • Moon phase. Many builds use a 24-hour day and night disc with a printed moon, not a 29.5-day cycle.
  • Week hand. Some copies drop the week pointer and print a fixed scale on the flange.
  • Weight. Steel copies land close to the real weight. Gold-plated copies feel light, since the case is brass or steel under the plating.

Movement options

Three builds show up in listings. One uses a Miyota 9015 with a calendar plate on top. One uses an ETA 2824 clone with the same add-on plate. One uses a custom plate on a thin automatic. None of the three is a perpetual calendar. Ask the seller for the base movement name before you pay. A real 5134 has a free-sprung balance and a 21,600 vph... no, 19,800 vph rate, so timegrapher numbers near 19,800 vph point to a different caliber.

Checks before buying

  1. Ask for a caliper photo of case thickness.
  2. Confirm the month disc advances with the date, not with a pusher.
  3. Check the leap year window at 3 o'clock and the year it points to.
  4. Request timegrapher numbers and a rate reading.
  5. Ask about gaskets. Most copies ship untested. Do not swim in one.

Legal and service notes

Counterfeit watches are illegal to import into the United States. Customs can seize a shipment, and the buyer carries the loss. Audemars Piguet will not service a copy, and parts for the calendar plate are hard to source. Resale value is low and depends on the factory batch.