Patek Philippe is one of the world’s oldest and most prestigious luxury watch manufacturers, and its timepieces are unrivaled when it comes to their enduring value and collectibility. Nine out of the top ten most expensive watches ever sold at auction are currently represented by Patek Philippe models, and the first step to navigating this ultra-exclusive side of horology is learning how to understand Patek Philippe reference numbers.
Every single Patek Philippe watch is formally assigned a corresponding reference number, and becoming fluent with this numbering system can tell you quite a lot of information about a watch, such as the model, its materials, certain physical attributes, and even the dial iteration that is fitted to it. However, the “rules” that apply to Patek Philippe reference numbers are often accompanied by exceptions, and learning how to read these seemingly senseless combinations of letters and digits requires a small understanding of Patek Philippe’s offerings, and how the brand chooses to structure its catalog.
Why Patek Philippe Reference Numbers Are Important
Although Patek Philippe watches are often referred to by their model names in mainstream conversations, it is really their reference numbers that most accurately describe them, and once you move beyond the most basic levels of discussion, reference numbers become the most efficient way to talk about models and an integral part of the greater collecting vocabulary. For example, there are three different versions of the Patek Philippe Nautilus Chronograph currently in production (as of January 2024), and referring to the watches by their reference numbers is the easiest way to convey details such as the material of the watch and whether it comes fitted with a leather strap or a metal bracelet.
With that in mind, the length of Patek Philippe reference numbers can differ, and two very similar models can often have different amounts of digits in their reference numbers, simply due to their case materials and whether or not the watch comes with a matching metal bracelet. Returning to our example of the Patek Philippe Nautilus Chronograph, all three of the current-production watches have reference numbers of different lengths, and aside from their dials (which actually doesn’t impact the amount of digits in their reference numbers), the only real differences between them are that one is a two-tone model and another is fitted with a leather strap instead of the collection’s signature integrated bracelet.
About Patek Philippe Reference Numbers
Modern Patek Philippe reference numbers generally consist of either three or four different parts, and they adhere to the format outlined in the example below, with the lowercase x’s representing numerals and the uppercase X’s representing letters.
xxxx/xxxxXX-xxx
The first part of a Patek Philippe reference number will always be a group of four digits, and these will describe the specific model. Whenever you hear collectors referring to Patek Philippe watches by four-digit numbers in shorthand conversation, these are almost always the numbers that they are referencing.
The second part of a Patek Philippe reference number can essentially be considered an optional section that offers additional information about the watch relating to its bezel, case, dial, and strap/bracelet. This second part consists of a backslash followed by a numeric code that typically spans anywhere between one and four digits, although some Patek Philippe models that are fitted with straps (rather than metal bracelets) omit this section entirely and jump immediately to the final two parts of their reference numbers.
The third part of a Patek Philippe reference number describes the materials of the watch, and unlike the other sections that use a numerical-based system, this part is represented by either one or two uppercase letters. All modern Patek Philippe reference numbers will have at least one letter in them, and aside from the first four digits that describe the model, the material code is arguably the second most important part of a Patek Philippe reference number.
The fourth and final section of a Patek Philippe reference number represents the dial iteration for the model, and it consists of a three-digit numeric code that is separated by a hyphen. With that in mind, it's important to note that this code only describes the iteration of the dial, rather than the style or color itself, which means that the first iterations of every Patek Philippe model will all share the same final three digits of their reference numbers.
Patek Philippe Reference Number Codes
Every digit or letter in a Patek Philippe reference number is significant, and while many rules for deciphering them are accompanied by exceptions, the different parts of a reference number can still tell you quite a lot of information about the type of watch and its context within Patek Philippe’s collection.
Model Number Codes
The first four digits of a Patek Philippe reference number will describe the model itself; however, they are not just randomly assigned to their respective watches. All Patek Philippe reference numbers will begin with a 3, 4, 5, 6, or 7, and the first digit will typically let you know whether the specific model is part of the men’s or women’s side of the brand’s catalog. For the most part, model numbers starting with a 3, 5, or 6 are men’s watches, while the ones beginning with a 4 or 7 are typically part of the ladies’ collection. That said, aside from the fact that watches themselves are inherently rather unisex items, there are also some notable exceptions to this system, such as a handful of Aquanaut Luce models that are numerically grouped with the men’s models, but will populate among the women’s watches on the brand’s official website.
The remaining three numerals that form the four-digit model numbers often adhere to general guidelines, although there can frequently be inconsistencies that prevent blanket rules from being applied across all of Patek Philippe’s catalog. Many watches with similar designs will feature the same first two digits for their reference numbers. For example, most full-size Nautilus watches have 57xx reference numbers, while their chronograph-equipped equivalents have reference numbers that follow some type of 59xx format. However, there are other general guidelines relating to these numbers, and if a model number ends in xx96 it is often a flat-bezel Calatrava, while if it ends in xx30 it is usually some type of worldtimer.
Watch Attribute Codes
The second “optional” part of a Patek Philippe reference number comes after the backslash, and it will offer additional information about the watch that relates to its case, bezel, dial, and strap/bracelet. Unlike the model number code, which can be a bit nebulous, this section follows a more rigid format, and (for the most part) it adheres to the numbering system outlined below.
- xxxx/1 — Metal bracelet
- xxxx/50 — Decorated dial (enamel, gem-set, engraved, etc.)
- xxxx/200 — Gem-set case (brilliant cut)
- xxxx/300 — Gem-set case (baguette cut)
- xxxx/400 — Gem-set case (high jewelry)
- xxxx/500 — Engraved case
- xxxx/600 — Case with enamel or lacquer
- xxxx/700 — Case with inserts (gold or gem-set)
- xxxx/900 — Mixed finishing techniques (diamonds with enamel/etc.)
With that in mind, these numbers can also be combined, which makes deciphering this section the most complicated part of reading Patek Philippe reference numbers. For example, the fully iced-out version of the ladies’ Nautilus is the reference 7118/1450G-001, and the “1450” part of its reference number is actually a combination of three different attributes from the list above. The “1” comes from the fact that the model is fitted with a matching white gold bracelet, the “400” denotes that it features a diamond-encrusted case, and since its dial is also paved in diamonds, this model qualifies as having a decorated dial and it therefore has an extra “50” integrated into this section of its reference number.
One important detail to always note when looking at a Patek Philippe reference number is whether it even has this second “optional” part at all. While the inclusion of a backslash followed by a series of digits doesn’t always guarantee that the watch has a metal bracelet, any Patek Philippe watch with a bracelet will have “/1…” added to the end of its four-digit model number. For example, the rose gold Nautilus Moon Phase is the ref. 5712/1R-001 when it is fitted with a bracelet, while it is the ref. 5712R-001 when paired with a leather strap, and that extra “/1” is simply there to denote that one of them is the bracelet-equipped model. If you don’t see this section in the reference number at all, then the watch is fitted with some type of strap.
Case Material Codes
While the model numbers and attribute codes can be a bit open-ended and difficult to decipher, the third part of a Patek Philippe reference number follows a simple and rigid system that is used to represent the case material of each watch. Unlike the rest of Patek Philippe’s reference numbers, the case material codes use letters (rather than numerals), and the letter codes themselves stand for the first letter in the French name of the metal that it represents. For example, the word “acier” means “steel” in French, so the stainless steel Patek Philippe models all have an “A” in their reference numbers. Meanwhile, the word “jaune” means “yellow” and this results in the yellow gold watches having a “J” as the third part of their reference numbers.
At the present time, Patek Philippe exclusively uses various types of metal for its cases and bracelets, which means that the brand’s material code system does not include letters for some of the more modern and experimental case materials such as ceramic or carbon fiber. While there is always the possibility of new materials working their way into the brand’s catalog and expanding upon this list, the third section of a Patek Philippe reference number will consist of one of the following letter codes.
- A — Stainless Steel
- J — Yellow Gold
- G — White Gold
- R — Rose Gold
- P — Platinum
- T — Titanium
- JA — Stainless Steel & Yellow Gold
- AR — Stainless Steel & Rose Gold
- PR — Platinum & Rose Gold
One additional point worth noting is that while “blanc” translates to “white” in French, “gray gold” is another common term for white gold, and the Patek Philippe watches with white gold cases have the letter “G” in their reference numbers to represent the French word “gris” (which means gray). Furthermore, any time you see two letters for this section, that implies the watch is a two-tone model and features two different metals. For example, the ref. 5980/1R-001 is the full rose gold Nautilus Chronograph, while the two-tone version is the ref. 5980/1AR-001, and that additional “A” in this part of its reference number is simply there to denote that it features both stainless steel and rose gold components.
Dial Iteration Codes
The final section of a Patek Philippe reference number consists of a hyphen followed by a three-digit numerical code, and this signifies the dial iteration that is fitted to that particular watch. Although this section provides absolutely zero information about the color or appearance of the dial, it does offer a small amount of insight into how many different dial variations have been fitted to that specific model.
The first dial iteration of any Patek Philippe watch will always have “-001” at the very end of its reference number, and this remains true regardless of the specific model or the color of dial that is fitted to it. However, the second dial iteration for that watch typically receives “-010” at the end of its reference number, while the third version has “-011” and the fourth gets “-012” (there are some notable exceptions). For example, the first version of the stainless steel Nautilus 5711 with a blue dial was the ref. 5711/1A-001, and when Patek Philippe slightly updated the model in 2006 and released a white dial version alongside it, the new blue dial model was the ref. 5711/1A-010, while the white dial version was known as the ref. 5711/1A-011.
However, where the exceptions come into play is when it comes to the two ultra-exclusive versions of the stainless steel Nautilus 5711 that were both released in 2021 to celebrate the final year of this fan-favorite model’s production run. The version fitted with the dark green dial is known as the ref. 5711/1A-014, while the limited-edition Tiffany & Co. model that has a Tiffany-signed dial in the famous luxury retailer’s signature shade of blue is the ref. 5711/1A-018, and there certainly weren’t three additional dial variations that appeared in the handful of months between when these two models were announced. Similarly, while the first Nautilus Travel Time Chronograph with a black dial is the ref. 5990/1A-001, Patek Philippe entirely skipped the “-010” designation for this series, and when the updated version with a blue dial appeared in 2022, it was known as the ref. 5990/1A-011.
How to Read Patek Philippe Reference Numbers
The easiest way to read a Patek Philippe reference number is to start with the first part, which is the four-digit model number. In most cases, the very first digit will immediately tell you whether it is a men’s or women’s watch, and the remaining three digits will tell you the specific model, which will allude to its size, functions, and movement. Memorizing key models and their general numerical trends will help you navigate the slightly daunting world of Patek Philippe reference numbers, although given the numerous exceptions that exist within the brand’s system, there aren’t any firm rules that can be applied across the entire catalog.
After looking at the four-digit model number, the next most useful piece of information will be the letter code that corresponds to the materials of the watch. Not all Patek Philippe reference numbers have a backslash followed by the additional watch attribute section, and given how multiple numerical codes can often be combined on the brand’s more elaborate models, it is often best to briefly skip past this section, and then circle back once you have already determined both the model of the watch and its materials.
In many instances, you may not need to break down a Patek Philippe reference number any further than this step, since some models are fairly straightforward and only exist in a single configuration. For example, the rose gold version of the Aquanaut Travel Time is the ref. 5164R-001, and since there has only been one execution of this particular model (at least at the time of writing), “5164” and “R” are the only relevant pieces of information that are included in its reference number until Patek Philippe releases a different version of the watch.
However, for certain other Patek Philippe watches, you will sometimes need to look at the watch attribute and dial iteration sections of their reference numbers in order to fully ascertain the specific watch and its exact configuration. For example, the standard time-and-date stainless steel Aquanaut is known as the ref. 5167A-001 when fitted with a rubber strap, although it is the ref. 5167/1A-001 when paired with a stainless steel bracelet. Similarly, the white gold Aquanaut Chronograph with a blue dial is the ref. 5968G-001, while its olive green dial counterpart is known as the ref. 5968G-010.
If you don’t feel like memorizing some of the more in-depth details relating to the various watch attribute and dial iteration codes, one thing you can always do when looking at a Patek Philippe reference number is to verify whether or not it even includes the second “optional” section at all. If the reference number lacks this section part entirely, then you can be certain that the model is supposed to be fitted with some type of strap instead of having a matching metal bracelet. Conversely, if the reference number has “/1…” following its four-digit model code, then you can virtually guarantee that the watch in question is supposed to have a matching bracelet in the same metal as its case.
Lastly, it’s worth mentioning one final time that while this guide contains all of the information you need in order to fully be able to understand Patek Philippe reference numbers and decipher their meaning, many of the “rules” should really be viewed as guidelines that generally hold true when applied to the brand’s models. Even within Patek Philippe’s current-production catalog, there are numerous instances of specific watches having reference numbers that defy the conventional system, especially when it comes to their attribute and dial iteration sections. However, understanding Patek Philippe reference numbers is an integral part of being able to decipher some of the nuances that make each one special, and it is a valuable skill for anyone who plans to collect this legendary Swiss manufacturer’s watches.