Below is some useful information on Rolex watches and the Rolex watch company. There are some links to Rolex specific web-sites, resources, book recommendations and accessories. If you know of something which should be included on this page please let me know and I will add it.

There are two sets of numbers generally found on Rolex watches. These are the model numbers and the serial numbers. These numbers are generally found between the lugs or horns on the watch, so the bracelet or strap must usually be removed to see them properly. The serial number can be found between the lugs at the 6 O’clock position and the case reference or model number between the lugs at the 12 O’clock position. These numbers are also found on the inside and outside of the case backs on some of the vintage Rolex models or in a combination of both.

The model number: – The model number is usually found between the lugs at the 12 O’clock position. The number is usually four or five digits long and can be split into two separate groups or codes which describe the model and case using the table below. The first two or three digits of the code are used to describe the type of watch. The second from the last digit has no confirmed accurate meaning on its own and can be ignored. The last digit is the code used to describe the case material that the watch case is made from.

Type of Watch First two or three digits

Oyster Perpetual 10 & 140

Oyster Perpetual Chronometer 142

Oyster Perpetual Date 15 & 150

Thunderbird Bezel DateJust 16 & 162

Daytona Cosmograph 165

Sea Dweller 16 & 166

Submariner Oyster Perpetual 55, 140 & 653

Oyster quartz Datejust 170

Oyster Perpetual Date 65 & 66

Yacht Master 166, 686 & 696

Lady Oyster Perpetual 67 & 671

Lady Oyster Perpetual Datejust 65, 69, 691 & 692

Airking 55 & 140Б

Oyster Perpetual Date Chronometer 15 & 150

Oyster Perpetual Datejust 16 & 160

Daytona Manual Wind 62

Explorer 165

Submariner16, 166 & 168

GMT Master 167

Oyster Perpetual Date 18, 180, 182 & 183

Oyster Quartz Date 190

Midsize Oyster Perpetual DateJust 682

Lady Oyster Perpetual Date 65, 69, 691 & 692

Type of Case Material Very Last digit

Stainless Steel 0

Yellow Gold Filled 1

White Gold Filled 2

Stainless Steel & Platinum versions – 2000 model 2

Stainless & Yellow Gold 3

Stainless & White Gold 4

Gold Shell 5

Rose Gold versions – 2000 model 5

Platinum 6

14k Yellow Gold 7
18k Yellow Gold 8
18k White Gold 9

Midsize Oyster Perpetual DateJust (6827/3)
Ignore the second from last number (6827/3)
Stainless steel and 18ct Yellow Gold (6827/3)

NOTE: The difference between “DATE” and “DATEJUST” models.

Gents Datejust 20mm case (measured between the lugs)
Gents Date 19mm case (measured between the lugs)
The Date model is 2mm smaller in overall diameter than the Datejust.

Ladies Datejust Gold bezel fitted to case
Ladies Date Steel bezel fitted to case

The serial number: – The serial number of a Rolex watch can usually be found between the lugs of watch at the 6 O’clock position. There has never been full agreement about the case numbers on early Rolex Oysters. The company has refused to release details from their archives and the market has been left to flounder around with insufficient data to establish a correct dating/serial number sequence.

However; help is at hand due to the fact that most of the early Rolex Oysters were sold in the UK they bear British hallmarks because it was a legal prerequisite for all precious metal items sold in Britain to be hallmarked by a government department. Hallmarking began in Britain around the late 12th Century (eight hundred years ago) making the hallmarking regulations most certainly the oldest piece of consumer legislation still in effect. The hallmark on each watch case comprised three parts; a standard mark, giving the purity of the metal (silver, 9/14/18/22 carat gold), the assay office mark (where it was hallmarked) and the date letter (the year it was assayed). Using the date letter, which gives us the year in which the watch was sent to the assay office (because the watches could not be sold without a hallmark, the empty cases were sent for hallmarking and then returned to Switzerland to have the movements fitted and then returned to the UK for sale; so the hallmark date would be close to the date at which the completed watches would leave the factory). When we then compare this to the case number, it is possible to draw up a table of dates and case numbers. However due to the intervention of WW II in 1939, the numbers cease at this point; being able to date the watches produced between 1926 and 1939 is a considerable improvement on the previous situation we all faced.

The next problem arose in the 1950s. Whilst it took Rolex almost 30 years (from 1926 to 1953) to use all the numbers between 20,001 and 999,999; at this point the obvious thing to do would have been to add a seventh digit to their case numbering machine(s) and continue into the millions. Rolex, as any student of the company will tell you, was never a company to follow the obvious path and so they chose to re-use previously issued numbers on the new cases. They, once again, chose not to follow the most logical path and begin at 0001; rather they began at 100,001 once again, a number previously used in the midst of WW II.

Fortunately when they began to reuse these numbers it was during the period when they were also stamping the date of construction inside the case back; this code consisted of a roman numeral I, II, III or IV representing the four quarters of the year and the last two digits of the year (for example II 54, representing the period April to June 1954). Using these date codes it is now possible to give definite dates to the previously uncertain period in the mid 50s. It was not until the late 50’s that Rolex began to use the seventh digit and from this point the numbering sequence became logical and able to be followed with any hope of accuracy.

The period in which logic was any use lasted shorter than anyone could have hoped; after Rolex reaches 9,999,999 they chose to initiate a new sequence based on the letters RLEX, the letter “O” was left out because of its resemblance to the number “0”. The new sequence began in 1987 and ran through to November 1991. Then a completely new system of case numbering was brought in and is as follows:

“S” serial numbers were introduced in 1993 and W ones first came in during 1994 and “T” serial numbers were first introduced in May 1996, but all these are still current; with this new numbering system numbers are generated almost randomly. The reasons for this were not disclosed to me, despite asking the question. I was met with the telephonic equivalent of an “enigmatic smile”. If you think things are now really confused……..it gets worse!!

The letter U was introduced in August 1997; and ran concurrently with S, T &W. However, things were not yet complex enough for Rolex, so the letter A was introduced in November/December 1998 and will also run concurrently with P which was introduced in early 2000.

Please note that Rolex are now using the prefixes “A” and “P” & randomly assigning numbers; therefore the exact date of production can only be ascertained by access to the records kept at Rolex, Geneva.

“Copyright 1996/2000 James M. Dowling & Jeffrey P. Hess, from ‘The Best of Times Rolex Wristwatches’, published by Schiffer Publishing Limited”

Note: The above Rolex Oyster case Serial number list is as accurate as the current information available will allow. The above chart will not be accurate for Non Oyster watches such as Chronographs, Dress, Cellini models and the Tudor oyster range of watches.

Replacement cases from Rolex will usually (if not always) have a 4,4xx,xxx serial number, no matter the model. This is a standard so that Rolex Service Centers can immediately identify an authentic replacement case.

Rolex movement Calibre’s: Below is a simple guide for interpreting the more modern Rolex Calibre Numbers used on Rolex movements. Most calibre numbers are stamped on the automatic bridge or on the train bridge of modern Rolex movements. Some of the older and vintage calibre’s are stamped on the base plate near or under the balance wheel.

The calibre number is sometimes called the movement number. The majority of Rolex calibre numbers have four digits.

The first digit shows the category type of movement fitted.
1st Digit/Movement Category type
1 Early movements (1950-1979 approx).
2 Ladies movements.
3 Gents movements.
4 Chronograph movements (later models).
5 Quartz Oyster movements.
6 Quartz dress watch movements

The second number emphasizes the age group of the movement.
2nd Digit/Age group of movement
0 1st group.
1 2nd group.
2 3rd group

The final 2 digits designate the functions and complications of the calibre.
Last 2 Digits/Functions of Calibre
30 No date mechanism fitted.
35 Date mechanism only fitted.
55 Day and date mechanism fitted.
75 24 hour hand fitted (Explorer and GMT models).
85 Adjustable 24 hour hand fitted

Ladies Calibre (2135)
Second age group (2135)
With date mechanism (2135)

NOTE: This formula does not apply to early calibre movements. For example a calibre 1575 will not always be fitted to a watch with a 24 hour hand.

Names used by or registered by Rolex other than “Rolex”:

Archeo, Aqua, Brandcard, Brex, Cestello, Cellissima, Chronautic, Cybernaut, Danaos, Elvira, Egyptian, Genex, Imperial, Lilliputian, LON, Lonex, Marconi, Milgauss, Metropolitan, Moneda, Ondeo, Omigra, Oyster, Oysterdate, Pearlmaster, Plage, Prima, Prince Dauphin, Prince, Rolco, Rolexis, Roliseum, Rollesor, Rolwatco, Royal, Sousmarin, Space Dweller Stratosphere, Tru-beat, Tudor, Unicorn Lever, Unicorn, Viceroy, Waferthin, Wicket, W/D, X/L, Zerographe.

Rolex related Web-sites:
Montres Passion – 3D animations explaining how mechanical watches work and how watches are made.
Rolex – The official web-site.
More coming soon…………