History of Rolex Serial Number

          Everyone can spot the "Serial Number" of a Rolex on the lugs, the inner rim of the dial, or on the case back of older models. It consists of a combination of numbers and letters. Many may wonder why there is always a question about the Serial Number or series when buying a Rolex. We will explain the principles and history behind the production of Serial Numbers for you to understand.

          1927 was the year Rolex first stamped a Serial Number on the case of every Rolex produced. It is said that the first number did not start at 1, but at approximately 20,000.

          By 1953, the serial numbers reached 999,999. Instead of using a 7th digit or moving to the millions, Rolex decided to start over. Surprisingly, rather than starting from 000001 or 20,000 as before, Rolex restarted at approximately 10,000, or perhaps slightly less.
          During that same period (approximately 1953–1959), Rolex also introduced a date stamping system using Roman numerals (I, II, III, IV) to indicate the quarter, followed by two digits representing the year. For example, III53 meant the watch was produced in approximately the third quarter of 1953.

          In 1960, the serial numbers reached 999,999, so Rolex decided to enter the millions by adding a 7th digit, which was used for many years thereafter.

          In 1970, Rolex stopped stamping serial numbers on the case back, likely realizing that engraving the Serial Number on the lug or the edge of the case—which is hidden by the strap—was sufficient, and that case backs could be swapped out.

          In 1987, the serial numbers reached 9,999,999. Instead of starting with an 8-digit number, Rolex began using an A-Z prefix. Rather than starting with A, the brand began with the letters in its name: R, followed by L, E, and X (using O because it resembles the number 0). After completing the word ROLEX, the brand continued with N, C, S, W, T, U, A, P, K, Y, F, D, Z, M, V, and G, although the logic behind the order is not clearly known.

          By 2010, Rolex was selling a million watches a year, and the letter combinations were exhausted. Rolex introduced the "Random Serial" system in late 2010. The principle was to create an 8-character string where each character could be a number or a letter, such as 5F28EDFK, 7876876F, or even 99999999 or AAAAAAAA. With the variety of 8-character alphanumeric combinations, it is possible to create 36 to the power of 8 (approx. 2.8 trillion) different combinations. However, Rolex does not use O or I to avoid confusion with the numbers 0 and 1, leaving 34 to the power of 8, which still provides over 1.7 trillion possible combinations. This means that even if Rolex continues to sell a million watches every year, it would take 1.785 million years to run out of numbers. The downside of this system is that it eliminated the ability to identify the production year based on the serial number.