Perpetual Calendar
Perpetual Calendar is a complication that automatically shows correct dates including leap years — no manual adjustment until 2100 (Gregorian rule exception). Patek 5320G trades at THB 4.2M–5.5M, AP Royal Oak Perpetual 41 at THB 2.8M–3.8M, Rolex Sky-Dweller Annual Calendar at THB 650,000–820,000 (Annual, not Perpetual).
Perpetual vs Annual vs Simple
Simple Calendar (Date)
- Shows date number only
- Manual adjust each month with 30 or 31 days, and February
- Example: Rolex Submariner Date, Datejust
Annual Calendar
- Shows day + date + month
- Self-adjusts every month except February (manual adjustment 1×/year)
- Example: Patek 5396, Rolex Sky-Dweller, Longines Master Annual Calendar
- Premium over simple: +60–80%
Perpetual Calendar
- Shows day + date + month + year/leap year
- Self-adjusts every month including February (28/29 days)
- Knows leap year every 4 years
- Will be wrong in 2100 due to Gregorian rule (years divisible by 100 but not 400)
- Example: Patek 5320G, AP Royal Oak QP, Lange 1815 Perpetual
- Premium over Annual: +80–150%
- Premium over Simple: +200–400%
Secular Perpetual
- Adjusts leap year exception correctly — works through 4000+
- Example: Franck Muller Aeternitas Mega 4
Mechanism
Perpetual calendar watches add:
- Date wheel — 31 positions
- Month wheel — 12 positions
- Year wheel — 4 positions (leap year cycle)
- Lever system — tells mechanism whether the month has 28/29/30/31 days
Parts count added:
- Simple date: 5–8 parts
- Annual: 30–40 parts
- Perpetual: 100–150 parts
Bangkok 2026 pricing
Patek Philippe Perpetual
| Reference | Model | Full Set price Jun 2026 |
|---|---|---|
| 5320G | Perpetual Calendar white gold | THB 4,200,000–5,500,000 |
| 5236P | In-line Perpetual Calendar platinum | 6,500,000–8,200,000 |
| 5327G | Perpetual Calendar with day-of-week | 5,800,000–7,200,000 |
| 5740/1G | Nautilus Perpetual Calendar | 9,500,000–12,500,000 |
| 5270G | Perpetual Calendar Chronograph | 8,500,000–11,000,000 |
AP Perpetual
| Reference | Model | Price |
|---|---|---|
| 26574ST | Royal Oak Perpetual 41 steel | THB 2,800,000–3,800,000 |
| 26574OR | Royal Oak Perpetual rose gold | 4,200,000–5,400,000 |
| 25820ST | Royal Oak Perpetual 36 (vintage) | 1,650,000–2,200,000 |
Annual Calendar (not Perpetual)
| Reference | Model | Price |
|---|---|---|
| Rolex Sky-Dweller 326934 | Steel | THB 650,000–820,000 |
| Patek 5396G | Calatrava Annual Calendar | 2,450,000–3,100,000 |
| AP Royal Oak Annual 26574 | (Annual variant) | 1,800,000–2,400,000 |
Service complexity
Perpetual Calendar service:
- Patek Geneva: THB 85,000–150,000 (full)
- Patek service certificate: 2-year warranty
- Service interval: 5–7 years (don't exceed)
- AP Service: THB 95,000–180,000
Service cost is high because:
- Disassembly of 100+ parts
- Leap year mechanism test in 4-year simulation
- Multi-position recalibration
Resale impact
Perpetual functioning normally + recent service papers
- Baseline + 5–10% premium
Perpetual with wrong date (needs adjustment)
- -8 to -12% (Service Centre adjusts)
Perpetual mechanism broken
- -20 to -35% (parts replacement complex)
Perpetual leap year mechanism not working
- -25 to -40% (full service required)
Recommendations
Buying Perpetual
- Test leap year mechanism — set date to Feb 28 → next-day shows Feb 29 (leap) or Mar 1 (non-leap)
- Verify month indicator — advance date past 31 → month rolls automatically
- Check service history — recent service is critical
- Patek/AP specialist verification before purchase
Selling Perpetual
- Service at Authorised Service Centre before sale (if 5+ years from last)
- Demo function to dealer
- Route to auction — Auction House Thailand has dedicated collectors
- Preserve documentation — instruction manual, service papers, original receipt
Send Perpetual photos via LINE — we route to Patek/AP specialists for accurate valuation.
Sources: Patek Philippe Perpetual Calendar technical guide · AP Royal Oak QP documentation · WatchCharts perpetual calendar premium index