The Short Answer

A fake Audemars Piguet Perpetual Calendar gives itself away in three places: the hand count, the depth and printing of the subdials, and the price. Genuine Royal Oak Perpetual Calendar references such as the 26574 are selfwinding perpetual calendars with no running seconds hand, a moon phase disc cut from metal, and a hand-finished movement behind a sapphire caseback. Copies use a printed moon phase, a flat dial, an off-the-shelf automatic movement, and a price in the hundreds or low thousands.

Work through the checks below in order. Treat the first clear mismatch as proof the watch is not genuine.

What You Need

  • The exact reference number you are verifying, for example 26574ST or 26579CE
  • A 10x jeweler's loupe
  • A digital scale that reads to 0.1 g
  • Current market pricing for that reference from a dealer listing or auction result
  • Daylight or a bright lamp with a neutral color temperature

Step-by-Step Checks

  1. Read the reference number and serial on the caseback, then confirm that reference exists in the Audemars Piguet perpetual calendar line.
  2. Compare the case diameter to the published spec for that reference, which is 41 mm on the Royal Oak 26574, using calipers or a ruler across the bezel.
  3. Count the hands. A genuine perpetual calendar in this family carries two central hands, hour and minute, with no running seconds hand.
  4. Examine each subdial under the loupe and look for cut apertures with crisp, polished edges rather than printed circles with soft borders or ink bleed.
  5. Study the moon phase. Genuine discs are metal with applied moons and stars; fakes show a flat printed disc that looks glossy or washed out.
  6. Confirm every indication exists and is spelled correctly: day, date, month, leap year, week on the 26574, and moon phase.
  7. Advance the calendar a few days and watch each indication move. Lagging or misaligned numerals point to a modified base movement rather than a real perpetual calendar calibre.
  8. Turn the watch over and inspect the movement: look for beveled bridges, circular graining, a skeletonized rotor with the AP crest, and engraved lettering, not stamped or glued-on decoration.
  9. Check the metal hallmark and fineness stamp on gold and platinum references, and look for gold plating wearing thin on the lugs, crown, or clasp of a steel piece.
  10. Inspect the bracelet and clasp. Genuine Royal Oak links carry sharp polished chamfers on every edge with even gaps; fakes show rounded bevels and shallow screw slots.
  11. Match the serial on the caseback to the warranty card, box label, and any service paperwork before you accept the sale.

Price Reality Check

Genuine Audemars Piguet perpetual calendars trade well into six figures on the secondary market. A seller offering a "new" 26574 for a few thousand dollars is not selling a bargain. That price gap is the single strongest signal, stronger than any dial detail you can inspect through a loupe.

If You Already Bought One

  • Stop wearing the watch and photograph it from every angle, including the caseback and clasp.
  • Keep the listing page, messages, receipt, and payment record.
  • Contact your payment provider or card issuer and request a chargeback for a misrepresented item.
  • Report the sale to the platform where it happened and to your local consumer protection office.