Today, we look at the new Jaeger-LeCoultre Master Ultra Thin Perpetual Calendar. This is one of my favorite models from the brand and certainly warrants attention whenever it’s updated. It’s never easy to cleanly pack in so many complications, but JLC seems to have pulled it off again.

You can call me a heretic, but I have little love for highly complicated watches. I love chronographs, but that’s an exception because I normally enjoy an unadorned, simple dial. The Jaeger-LeCoultre Master Ultra Thin Perpetual Calendar is a bigger exception, though. I blame Gerard because of his ’90s Master Control version of this model. It’s classy without looking too busy. The newest models introduced at Watches and Wonders 2024 carry the torch faithfully.

Jaeger-LeCoultre Master Ultra Thin Perpetual Calendar rose gold

The Jaeger-LeCoultre Master Ultra Thin Perpetual Calendar

The new Jaeger-LeCoultre Master Ultra Thin Perpetual Calendar comes in three different variants. An 18K rose gold model is available with an eggshell dial. It comes with a plain or diamond-set bezel with 60 stones. The other option is steel paired with a silver sunray dial. No matter which model is chosen, the watches are fitted to a black alligator strap with a folding clasp. As far as the case size, JLC has resculpted the 39mm case to make the lugs longer and thinner. The thickness is admirable at just 9.2mm, yet the water resistance is useful at 5 ATM.

The heart of this watch is its in-house caliber 868. An update versus the prior model brings the power reserve from 38 to 70 hours. JLC mentioned that it wanted to provide the ability to leave the watch off the wrist for a full weekend without the need to reset it on a Monday morning before work. If the movement is kept running, it will not need adjustment until 2100, and it’s “smart” enough to encompass leap years. The movement is viewable via a sapphire crystal on the case back and contains high levels of finishing and a gold oscillating weight.

Complications in an elegant package

The updated Jaeger-LeCoultre Master Ultra Thin Perpetual Calendar contains slight changes to its dial versus its predecessor. For example, the applied indices are thinner, and the various windows on the dial now contain layered bevels. The changes are subtle, but they appear more finely detailed. The layout and functionality do not change, which includes a small corrector button on the left side of the case.

The watches contain central hour and minute hands with a blued steel seconds hand. A moonphase display sits at the top of the dial, while the day of the week is at 9 o’clock, the date is at 3, and the month is at 6. A display shows the year between 7 and 8 o’clock. Note the small window above the central pinion. This turns red when it is unsafe for the user to set the time or calendar functions as it could damage the movement. The central hands have slots so as not to obscure this window.

Jaeger-LeCoultre Master Ultra Thin Perpetual Calendar rose gold with diamonds

Thoughts and pricing

Complicated watches don’t typically turn my head, but I fancy a piece like this Ultra Thin Perpetual Calendar. It’s an incredible mechanical complication that should fit in any collector’s stable. I’ve always liked how JLC lays out its dials, and this newest version brings enough tweaks to improve it over the prior one. Plus, a 70-hour power reserve is quite useful. When it comes to pricing, the steel version will cost €31,100. The gold model is priced at €44,500, and the diamond-set model is €52,500. That’s not insignificant money, but compared to examples from Lange, Vacheron, or Patek, the Jaeger-LeCoultre is a relative bargain.

For more information on the Master Ultra Thin Perpetual Calendar, visit the official Jaeger-LeCoultre website.

Watch specifications

Master Ultra Thin Perpetual Calendar
Q1142510 (rose gold with eggshell dial) / Q1142501 (rose gold with diamonds and eggshell dial) / Q114842J (steel with silver sunray dial)
Eggshell or silver sunray with applied indices
Case Material
Stainless steel / 18K rose gold / 18K rose gold with diamond-set bezel
Case Dimensions
39mm (diameter) × 9.2mm (thickness)
Case Back
Stainless steel or rose gold with sapphire crystal
Jaeger-LeCoultre 868: automatic perpetual calendar, 28,800vph frequency, 70-hour power reserve, 46 jewels
Water Resistance
5 bar
Black alligator with steel or rose gold folding clasp
Time (hours, minutes, seconds), perpetual calendar (day, date, month, year) with red security zone, moon phases
€31,100 (steel) / €44,500 (rose gold) / €52,500 (rose gold with diamonds)