If you just purchased a pre-owned or antique watch and want more information about it, the serial number can help you trace the company-owned database information of the watch. But where is this number? It depends on each watch, but here are a few tips for finding one.

If you have documents from the watch, the serial numbers should be there

You might save yourself some effort if you have documents of your watch, such as warranties, receipts, etc. A model number can be referred to as a “reference number,” while the serial number may be listed without any qualifications. If in doubt which one, see the note below about online databases.

See if there is an online database of company serial numbers

Oftentimes, you can find serial number databases online that will help you figure out the year your watch was made. Longines offers this service with free of charge for all of its watches. You simply email them the number from your watch and some pictures and then wait for a response.

Check the caseback of the watch

The watch serial number may be on the back of the case, this is especially for modern watches. However, you will have to learn to differentiate between a serial number and a reference number, which is a model number. When in doubt, do an internet search for each number along with the name of the watch company and see what comes up.

If the watch is a Rolex, check between its the lugs

Rolex places their model and serial number between the lugs of the watch. Take off your strap and you will see it right away. Model numbers are generally four, five, or six digits long, while serial numbers can be up to eight digits long. Again, if in doubt, plug the two numbers into Google with the word “Rolex”, and you will be able to tell which one is the model number and which is the serial depending on the search results.

If the watch has a transparent caseback, look at the movement

Is your watch a modern model with a sapphire caseback so you can see the movement from the back? It may be difficult to tell the serial number apart if it’s engraved on the movement from the back of the case, but it’s worth looking around, especially if you have a magnifying glass.

On the inside of the caseback

Open the caseback, there are some watches that include the serial number on it. A vintage Longines watch, featuring the watch serial number and model on the inside of the watch case.