How to Date your Jaeger-LeCoultre Atmos Clock

How to Date your Jaeger-LeCoultre Atmos Clock

November 17th 2024

Dating Your Atmos Clock 

A How TO GUide..

We are regularly asked by clients how would you go about dating your Atmos clock and we thought it was about time we offered a rough timeline on how to date your clock. First of all you will need to look for the clocks unique serial/reference number which is a sequence of numbers. As an immediate guide the lower the number the earlier the clock is in age, just be cautious that you are reading the correct numbers which will only ever appear in linear form one after another with no other characters. The serial numbers are typically are located either on the top of the regulator block as you look down on the clock from above or to the front of the clock just below the hands. There are some clocks which the serial number is not accessible unless it is accessed by a professional, in this case we would be happy to give you a rough date if you send us a photo of your model via our contact us page. These models include the non-skeletal models such as the lucite panel models or the wooden Gruen model amongst others.

Jaeger-LeCoultre Atmos Clock Dating Chart

Below we have added some examples of the reference numbers on different clocks and a chart to decipher the each model and age. The table contains a rough guide to dating your Atmos clock  with emphasis on a rough guide. This will give you an approximate age to the correct decade but is not an exact Jaeger-LeCoultre official chart so please bear that in mind.

There is a known ‘old wives tale’ that you can date your Atmos clock exactly using a specific formula, we have found this can be hit and miss but has some merit to the models containing six digits. This works by using the below formula, we have used the atomic clock photographed below as an example using the serial number 323321. You also use the figures 0.51 and 1954 which do not change.

Serial number broken down into the first four numbers for example 999999 would become 999.9

*Serial Number* X 0.051 + 1954 = year (first four numbers)

323321 – 323.3 x 0.051 + 1954 = 1970.4883

This would give you a date of 1970

This formula does not work for all clocks and I would only use it as a very rough guide for the six digit models (100,000 onwards), a bit of fun to try and date your Atmos!

Front of the Jaeger-LeCoultre Atmos Clock

Front of an earlier model jaeger-lecoutlre Atmos clock

Close up of the serial number on the movement 19976

The first example you can see that the serial number is located on the front plate of the movement below the hands, the number is 19976 so we know that is is the nineteenth thousand nine hundred and seventy sixth model. The second example below shows that the reference number is located on the top of the movement block when looking from above. This type is more common on your later models from approximately the 60’s onwards although that is only a rule of thumb.

Front of the mid century modern Jaeger-LeCoultre Atmos Clock circa 1970

Front of a 1970’s model jaeger-lecoutlre Atmos clock

Top of the Atmos clock showing where the serial number is located for dating

Jaeger-LeCoultre Atmos Clock serial reference number example

Close up of the regulator block showing the serial number 323321 on the top of the 1970’s Atmos clock.

We can establish the rough age of this model as it is the three hundred and twenty three thousand three hundred and twenty first model. Using the chart it shows that this model lies within the years circa 300,000 to 519,999 dating it to the 1970’s.

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