Rolex Reference Numbers: Difference Between 4, 5 and 6 Digits

One of the main draws of Rolex watches is their timeless design. From sports watches like the Submariner, to dress pieces like the Day-Date, many of Rolex’s models remain largely unchanged since the day they were introduced.

While Rolex watches remain true to their design ethos, that’s not to say they haven’t been improved over the years. Rolex is known to make very subtle changes for every reference, keeping the iconic design intact, while making gradual and meaningful technological improvements.

One way to tell the important features of your Rolex is through its reference number. Let’s explore the differences between 4, 5, and 6-digit reference numbers of Rolex watches.

Generations of the Rolex Yacht-Master

Rolex Reference Numbers: What do they mean?

While they may appear to be an arbitrary string of digits at first glance, Rolex reference numbers are the key to unlocking information about a watch’s production era, model type, bezel design, appearance, and even the materials used in its case and bracelet.

To go over it quickly, each digit of the Rolex reference number refers to the following details about the watch:

First two to four digits – Model Type or the family of watches it belongs to, such as the Datejust, Daytona, Yacht-Master, and the like
Second to the last number – Bezel Type, such as smooth, rotating, or fluted
Final digit – Material or the type of metal the watch is made of, such as steel or Everose gold
Letters – gems, colors, and other watch elements

Modern Rolex Sports Watches with Blue Bezels and Dials

For a full list of the legends for each digit, here’s our guide Rolex Reference Numbers Explained.

Rolex has used different lengths of reference numbers over the years, varying from 4 to 5, and 6-digit numbers. You can find it engraved between the lugs on the 12 o’clock side of the case. Here’s how to tell them apart:

Production Periods

The number of digits in a Rolex reference number can reflect the production era of a Rolex watch. With this in mind, the Swiss brand added digits to its reference number system by individual model, so there isn’t a single year when every single timepiece across the brand’s diverse range saw its reference numbers grow by one digit.

Generations of the Rolex Submariner

In general, most Rolex pieces that carry four-digit reference numbers were created before the late 1980s and are thus already vintage watches. Rolex started creating models with five digits in the late 1970s, and by the late 1980s, it had converted all of its models to five-digit reference numbers. Therefore, whether a five-digit Rolex is classified as vintage or discontinued is determined by its age.

In the 2000s, Rolex finally used six-digit reference numbers by prefixing a pre-existing reference number with a 1 or 2. Take, for example, the Explorer II. Although its reference number changed from 16570 to 216570, the core reference numbering scheme and the significance of each individual digit remained the same.

Rolex Reference Numbers with Letters

Rolex introduced the Cerachrom ceramic bezel in 2005. As a result, the introduction of six-digit reference numbers was complemented by the addition of two or four-letter extensions at the end of model numbers to signify the hue of the Cerachrom bezel that was affixed to a specific watch.

Rolex Datejust 36mm Steel Yellow Gold Watches with
Jubilee Bracelets, Fluted Bezels, and Champagne Dials

In the case of the Rolex Kermit ref 16610LV, the LV suffix stands for Lunette Vert or green bezel, whereas for the Rolex Milgauss ref 116400GV, the GV stands for Glace Verte or green glass.

On the other hand, models with two-tone ceramic bezels, such as the GMT-Master II Batman 116710BLNR, received four letters to the end of their reference numbers. The letters BL and NR stand for “blue” and “noir,” respectively, and connotes that the ceramic bezel is in black and blue.

Until recently, it was safe to say that a watch with a six-digit Rolex reference number was in current production. However, beginning around 2015, Rolex began retiring some six-digit models and replaced them with ones that featured either new movements and/or improved design elements – all while maintaining the six-digit reference number system.

Rolex Submariner models with Black Bezels and Dials:
ref. 1680, ref. 16610, and ref. 114060

Today, Rolex continues to employ the six-digit system, with just the first or second reference number changing to designate a “new generation” of that particular reference.

Rolex Luminescent Material

The lume used on the dial is another design detail that can be used to distinguish between 4, 5, and 6-digit versions. Since the luminous materials used in Rolex watches have changed over time, it’s possible that two different lume types are used on models with the same reference number.

Chromalight Dial of the Rolex Submariner Yellow Gold Black Dial Bezel ref. 126618

Radium was utilized until the early 1960s, tritium until the late 1990s, LumiNova until around 2000, Super-LumiNova up to the late 2000s, and Chromalight in 2008. For many years, Chromalight was utilized with Super-LumiNova until Rolex shifted completely to its own unique blue-glowing Chromalight material.

A Rolex watch is therefore assured to have a four- or five-digit reference number if it uses tritium or radium for illumination. Similarly, if the watch features Luminova or Super-LumiNova, it most likely has a five or six-digit reference number. Last but not least, a watch that uses Chromalight will undoubtedly have a six-digit reference number.

Rolex Crystals and Bezels

Rolex also modified the crystals used to protect their watch dials. The company previously used acrylic ones, but now employs sapphire crystals. This implies that Rolex references with five digits can feature acrylic or sapphire crystals depending on the model, whereas all pieces with six-digit numbers come with sapphire crystals.

Cerachrom Bezel of the Rolex Submariner Yellow Gold Black Dial Bezel ref. 126618

Rolex then eventually replaced all aluminum bezels in the Submariner and Sea-Dweller lines with Cerachrom, and also swapped the steel bezel of the Daytona for a Cerachrom counterpart. The Cerachrom also appears in a matte form in the Yacht-Master series.

This means that if your Rolex timepiece comes with a ceramic bezel, then it is guaranteed to be a piece with a six-digit reference number.

Rolex Bracelets

Lastly, we have the bracelet. From the iconic Oyster to the sophisticated Jubilee, Rolex watches are well-known for their bracelet designs that have been modified for robustness and ergonomics through the years.

The Oyster bracelet was released in the late 1930s and was patented in 1947. Initially, this type of band had straight lugs, but a few years later, Rolex fitted it with curvy “flush-fit” end links that precisely fit the case.

Generations of the Rolex Air King: ref. 5500, ref. 14000, ref. 114200, and ref. 116900

While the bracelets themselves were well-made, the end links have been the weakest point in all of these designs. They are the most heavily used links, and their hollow shape causes them to rattle over time. On top of that, they had an unsightly seam in a prominent location.

Rolex made an adjustment in the early 2000s to address this issue and added solid end and center links to their Jubilee and Oyster bracelets. Solid links are less prone to damage since there is less of an opening for dirt to enter.

The changes in Rolex reference numbers give us an insight to the evolution of the watches themselves. Whether it’s vintage or modern, each Rolex watch has its own set of unique features to offer. Explore our vast selection of Rolex watches at SwissWatchExpo.com.