What is Case size and lug-to-lug?
Width across the case, and the length tip to tip.
Short answer
Most wrists suit 36–40 mm cases with 44–48 mm lug-to-lug — measure, don't guess.
Case size and lug-to-lug when buying a wristwatch (quartz & automatic)
Width across the case, and the length tip to tip.
Why it matters: Lug-to-lug wider than your wrist overhangs and looks too big.
Look for: Most wrists suit 36–40 mm cases with 44–48 mm lug-to-lug — measure, don't guess.
Full Wristwatch (Quartz & Automatic) buying guide