While at first glance it may look like an arbitrary string of digits, the Rolex reference number is the key to unlocking information about a watch’s production era, type of model, bezel style, and material used. If you’ve ever wondered why Rolex has used different length reference numbers over the years, then read our general guide to the difference between 4, 5, and 6 digit Rolex reference numbers.
Productions Eras: 4, 5, and 6 Digit Rolex Reference Numbers
Vintage watches are typically classified as those more than 30 years old. Watches younger than three decades but not currently in production are sometimes called retro watches, but more often simply referred to as discontinued watches. Lastly, models that are part of the present Rolex catalog (Like the Rolex Daytona ref. 116500) are called current-production watches.
How many digits a Rolex reference number has can indicate the watch’s general production era. Rolex watches with four digits were typically made before the late 1980s, thus are considered vintage watches. For instance, the vintage Submariner 1680, the vintage GMT-Master 1675, the vintage Daytona 6263, the vintage Datejust 1601, and so on.
Rolex began producing models with five digits in the late 1970s and transitioned all models to five-digit numbers by the late 1980s. So whether a five-digit Rolex is categorized as vintage or discontinued comes down to its production era. For example, the Day-Date 18038, Sea-Dweller 16660, and GMT-Master 16750 are vintage Rolex models, while the Day-Date 18238, Sea-Dweller 16600, and GMT-Master II 16710 are not necessarily so.
In the 2000s, Rolex transitioned to six-digit numbers by either adding a “1” or “2” to the beginning of the reference. For example, the Explorer switched from 14270 to 114270, the Datejust from 16200 to 116200, the Submariner from 16610 to 116610, and the Daytona from 16520 to 116520.
Up until very recently, it was safe to assume that a six-digit Rolex number meant that it was a current production model. However, starting around 2015, Rolex began discontinuing six-digit models and replacing them with fresh versions with either new movements, upgraded design details, or both – while still retaining the six-digit format. Therefore, there are now both discontinued models and current-production Rolex models with six-digit reference numbers.
Luminescence, Crystals, and Bezels: 4, 5, and 6 Digit Rolex Reference Numbers
There are some design details on a Rolex watch that can help you tell the difference between a 4, 5, and 6 digit Rolex reference number. For example, the type of luminous materials used on Rolex watches has evolved over the years: radium until the early 1960s, tritium until the late 1990s, LumiNova until 2000, Super-LumiNova until the late-2000s, then finally, Chromalight. If the watch uses radium for luminescence, then it has a four-digit Rolex reference number. If the Rolex watch uses Super-LumiNova or Chromalight, then it’s likely a six-digit reference number – however, if it’s a service replacement dial, then the watch can be from any era.
Rolex also changed the type of crystals used to protect the dials of its watches. Originally, the company used acrylic crystals and today it uses sapphire crystals. The transition started slowly in the 1970s, picked up steam in the 1980s, and was completed by 1990. Except for the Rolex Quartz 5100, the Datejust 1630, and the Rolex Date 1530, all four-digit Rolex reference number watches were originally fitted with acrylic crystals. Additionally, all Rolex watches with six-digit reference numbers have sapphire crystals. Depending on the model, five-digit Rolex references can either have acrylic or sapphire crystals.
For most of its history, Rolex has used aluminum to make its bezel inserts. However, in 2005, Rolex introduced the Cerachrom ceramic bezel insert to the GMT-Master II collection. Eventually, Rolex replaced all aluminum bezels with Cerachrom ceramic across the Submariner, Sea-Dweller, and Daytona collections. So, if your Rolex has a ceramic bezel insert, then it is most definitely a six-digit reference.
In short, the evolution of the Rolex reference numbers from four, to five, to six digits mirrors the evolution of the watches themselves. Generally speaking, the longer the reference number, the newer the watch. Do you typically favor 4, 5, or 6-digit Rolex references? Leave us your thoughts in the comment section below.