Numbers are big in time keeping.
And they’re especially big in Rolexes.
Rolexes are serial numbered with a 4- to 8-digit number.
But they also have a reference number.
As soon as you start looking at Rolexes you’ll see them referred to as “references”.
These numbers, which are between 4 and 6 digits long (sometimes with added letters), describe the watch.

The model number here is the "Reference" it tells you everything you need to know about the watch's reference.
Knowing how they work is good Rolex knowledge.
And it’ll help you quickly know what to expect from any watch for which you have the reference.
Rolex reference numbers: the working parts
Rolex references are somewhat idiosyncratic and have developed over time. The system hasn’t been universally applied in the same way to all references at all times. References can fall in and out of production and it’s not possible, for example to do a quick dating from a reference with 100% accuracy.
However, it is a system.
1 - the whole number
The length of the number will help you know when the watch was made.
Four digits - generally made before the late 1980s
Five digits - transition to five digits began in the late 1970s and was pretty much done by the late 80s
Six digits - Made from the 2000s onward
2 - The watch family

The Air-King has been made since 1957 using various references.
The model of watch is described by the first digits in the reference:
1908:
525
Air-King:
43, 49, 55, 57, 65, 140, 114, 1169, 1269
Cellini:
41, 42, 51, 52, 53, 61, 66
Cosmograph Daytona:
62, 165, 1165, 1265
Date 34
15, 150, 115, 1152
Datejust 31:
682, 782, 1782, 2782
Datejust 36:
66, 16, 160, 162, 1162, 1262
Datejust 41:
1263
Datejust II:
1163
Day-Date 36:
65, 18, 180, 182, 183, 1181, 1182, 1183, 1282, 1283
Day-Date 40:
1182, 2282, 2283
Day-Date II:
2182
Day-Date Masterpiece:
189
Deepsea:
1166, 1266
Explorer:
1142, 1242, 2142
Explorer II:
165, 2165, 2265

This GMT-Master dates to 1960, early in the history of the "time zone" watch aimed at aircrew and nicknamed the Pepsi for its red/blue bezel.
GMT-Master:
65, 16, 167
GMT-Master II:
167, 1167, 1267
Lady-Date 26:
69, 691, 791, 792, 1791, 1793
Lady-Datejust 26:
690, 691, 791, 792, 1791, 1793
Lady-Datejust 28:
2791, 2793
Lady-Yacht-Master:
696, 1696
Milgauss:
65, 10, 1164
Oyster Perpetual 24:
760
Oyster Perpetual 26:
1762
Oyster Perpetual 31:
77, 1772, 2772
Oyster Perpetual 34:
102, 152, 1152, 1242
Oyster Perpetual 36:
1160, 1260
Oyster Perpetual 39:
1143
Oyster Perpetual 41:
1243
Oysterquartz:
170, 190, 191
Pearlmaster 29:
802, 803, 803
Pearlmaster 34:
812, 813
Pearlmaster 39:
862

It's very clear how pearlmasters were named.
Sea-Dweller:
166, 1166, 1266
Sky-Dweller:
3261, 3269, 3362
Submariner:
55, 140, 1140, 1240
Submariner Date:
16, 166, 168, 1166, 1266
Turn-O-Graph:
162, 1162
Yacht-Master 35:
686, 1686
Yacht-Master 37:
2686
Yacht-Master 40:
166, 1166, 1266
Yacht-Master 42:
2266
Yacht-Master II:
1166
(The numbers in the names here are the size of the watch.)
3 - Bezel type
The bezel is the outer rim of the watch face that clamps the crystal glass in place.
They can be just that, or they can move, in order to provide an extra function. Diver’s watches usually have a rotating bezel that allows a diver to mark a start time for example.
Rolex bezels are described thus in the Rolex system.
They are the fifth number in 6-digit reference numbers:
0 - Smooth
1 - Engine turned
2 - Engraved
3 - Fluted
4 - Bark or hand crafted
6 - Rotatable
7 - Various/other

Bezels are structural, but can bring extra information and fucntionality to a watch.
4 - Material
In 6 digit reference numbers the 6th number tells you what material the watch is made of. For shorter reference numbers, it’s the last digit.
0 - Stainless steel
1 - Everose Rolesor (Stainless Steel and Everose Gold)
2 - Rolesium (Stainless steel and Platinum)
3 - Yellow Rolesor (Stainless Steel and 18k Yellow gold)
4 - White Rolesor (Stainless Steel and 18k White gold)
5 - Everose
6 - Platinum
8 - 18k Yellow gold
9 - 18k White gold
After the numbers you may see letters.
These describe the colour of the bezel or any gemstones used in its decoration (and in one case the crystal colour):
BLRO: Bleu/Rouge or blue and red
BLNR: Bleu/Noir or blue and black
CHNR: Chocolat/Noir or brown and black
GV: Glace Verte: the green crystal found on Milgauss 116400GV
LB: Lunette Bleu or blue
LN: Lunette Noir or black
LV: Lunette Verte or green

LV for green in the legendary Submariner Hulk.
Some watches are set with gems, and these are recorded in these letter codes:
TBR: Tessellate Brillants or diamond set
TEM: Tessellate Emeraude or emerald set
SABLV: Saphirs Bleu Vert or blue and green sapphire set
SABR: Saphirs, Brillants or sapphire and diamond set
SACO: Saphirs Cognac or cognac sapphire set
SAFUBL: Saphirs Fuchsia Bleu or fuchsia (pink) and blue sapphires
SAJOR: Saphirs Jaune Orange or yellow and orange sapphire set
SANR: Saphirs Noir or black sapphire set
SARU: Saphirs, Rubis or sapphire and ruby set
Rolex References examples
The Rolex "Hulk" Submariner is reference 116610LV
The 1166 gives us the Submariner family.
The 1 gives us the engine turned bezel.
The 0 gives us stainless steel.
And LV gives us the green bezel that gives it its name.
Rolex Oyster Perpetual Celebration Dial is ref. 126000
1260 gives us the Oyster perpetual with 36 mm case.
Then we have a 0 for a plain bezel, with another 0 telling us it’s stainless steel.

The "celebration" is an Oyster Perpetual.
Buying pre-owned Rolexes today
Knowing your subject is the best way to get good value, good quality pre-owned Rolex watches.
We have some lovely luxury watches here.
And we’re always looking for more.
If you’d like to sell then drop us a line and perhaps we know a buyer for your piece.