Patek Philippe Cubitus Perpetual Calendar Skeleton 5840P: The First Grand Complication in a Square Case

Patek Philippe Cubitus Gets Its First Grand Complication: The Perpetual Calendar Skeleton 5840P

Patek Philippe has given its controversial Cubitus collection its most significant upgrade yet. The Perpetual Calendar Skeleton Reference 5840P-001 is the first Grand Complication in the Cubitus line, combining the brand's signature square-case design with a skeletonized dial, perpetual calendar, and large moonphase display — all housed in 950 platinum.

Design: Bold Enough for the Cubitus

The Cubitus debuted in 2024 as Patek Philippe's first new collection in 25 years. Its square case and horizontal stripe dial divided opinion from day one. The 5840P-001 doubles down on that identity, featuring a skeletonized treatment that reveals blue PVD-coated stripes behind the perpetual calendar registers.

The 45mm platinum case adds just 0.4mm in height (to 10mm) compared to existing Cubitus models. Three balanced registers display the perpetual calendar month, date, and day of the week, with angled baton indices in 18K white gold filled with white Superluminova lume surrounding the dial edge.

The Large Moon: A First for Regular Production

This is the first non-limited, non-anniversary Patek Philippe model in the regular collection to feature a large moon display. Rather than the traditional twin-moon disk, Patek Philippe opted for a single detailed moon against a starry background, completing one rotation every 29.53 days for a full lunar cycle. The last time Patek Philippe used such a mechanism was for its 175th anniversary in 2014.

Technical Specifications

Movement: Adapted for the Square

The Caliber 28-28 Q SQU is an evolution of the Caliber 240 Q, which forms the basis of most Patek Philippe perpetual calendars. Comprised of 313 total components, the movement is powered by a 22K gold micro-rotor and beats at 21,600 vph. The bridges are cut in parallel stripes matching the dial design, with blue blued screws and a Calatrava Cross engraved on the micro-rotor providing pops of color against the platinum.

The perpetual calendar mechanism accounts for leap years and varying month lengths, requiring no manual correction until March 1, 2100. The large moonphase display necessitated changes to the gear train for the slower-rotating disk.

What This Means for the Cubitus

The 5840P-001 signals Patek Philippe's commitment to growing the Cubitus line with its greatest complications. Earlier Cubitus models featured round movements inside their square cases — a design choice that drew criticism. The Caliber 28-28 Q SQU represents a dedicated effort to create movements that fit the Cubitus's unique proportions.

At 150,000 CHF and available without limited-edition restrictions, the perpetual calendar positions the Cubitus as a serious contender in the high-complication sports watch category — exactly where Patek Philippe likely intended it to be from the start.

Frequently Asked Questions

Q: How does the Cubitus perpetual calendar differ from the Nautilus perpetual calendar?
A: The Cubitus uses a modified Caliber 28-28 Q SQU with skeletonized bridges, while the Nautilus perpetual calendar uses the standard Caliber 240 Q. The Cubitus also features the large moon display, which is not available on the Nautilus perpetual calendar.

Q: Is the 5840P-001 a limited edition?
A: No. Unlike the Nautilus 50th anniversary pieces, the Cubitus Perpetual Calendar is part of Patek Philippe's regular collection with no production limits.

Q: What is the power reserve of the Caliber 28-28 Q SQU?
A: The movement offers 48 hours of power reserve, consistent with other Patek Philippe perpetual calendar movements in the 240 family.

According to aBlogtoWatch, the Patek Philippe Cubitus Perpetual Calendar Skeleton Reference 5840P-001 is priced at 150,000 CHF and is available now through authorized Patek Philippe dealers.

Discover more about high complications in our Complete Watch Buying Guide and read about The Evolution of Luxury Sports Watches.