Case diameter
Also called case size
Case diameter is the width of a watch case, usually measured across the case excluding the crown, and stated in millimetres.
It's the headline size buyers search by, although lug-to-lug length and case thickness also affect how a watch wears. Preferences for size shift over time, which can move demand for particular references.
Measure precisely and say how you measured, since brands and sellers don't always measure the same way.
Because buyers filter searches by size, an accurate diameter in your listing also affects how often the watch is found in the first place.
Related terms
Where this comes up
Pages on this site that use the term.
Learn the trade, not just the word
Plain-English guides to buying, pricing and selling watches as a business. Free, and written to be used at the counter.