Navitimer B19 Chronograph 43 Perpetuel Calendar

A perpetual calendar caliber is a mechanical movement that knows how many days each month has, even on leap years. Knowing that February has 29 days on a leap year may just be one single day, but the mechanical complexity behind it is hard to overstate. The perpetual calendar Caliber B19 incorporates an additional set of components programmed to know exactly when that extra day happens within the four-year cycle. To make things more complicated the five calendar indications: day, date, month, moonphase, and leap year, all advance instantaneously from December 31 to January 1.

The perpetual calendar complication alone is a remarkable achievement, but what makes the B19 especially ambitious is that this highly complex mechanism shares space with a chronograph. A chronograph is already one of watchmaking’s most demanding complications, operating independently from the standard time and responding to user input through start, stop, and reset pushers. The in-house Caliber B19 uses 374 components, yet fits within a case measuring less than 15mm thick, and 43mm in diameter.

Incorporating this caliber into the Navitimer represents the model’s highest expression to date—bringing together technical prowess and Breitling’s most iconic design.