Watch Size Calculator
Your wrist measurement tells you the watch case diameter, strap length and lug width that will look and fit right.
Find your watch size
How to measure
Measure your wrist
Wrap a soft tape (or a strip of paper) snugly around your wrist where the watch sits, just past the wrist bone. Or use our printable tape.
Read the case size
Case diameter is the main number watches are sold by. A proportionate case looks balanced on your wrist.
Check the lug width
Lug width (the gap where the strap attaches) sets which straps fit — match it when buying a replacement.
Taste matters too
Larger cases are in fashion; if you prefer a bigger or smaller look, adjust within the range.
Analog and smartwatches in a range of case sizes.
View on Amazon →Replacement straps — match your lug width in mm.
View on Amazon →Resize a metal bracelet to your wrist at home.
View on Amazon →Frequently asked questions
What size watch case for my wrist?
As a guide: under 15 cm wrist suits 34–38 mm, 15–17 cm suits 38–40 mm, 17–19 cm suits 40–44 mm and over 19 cm suits 44 mm and up.
What is lug width?
Lug width is the distance in mm between the lugs where the strap attaches. It determines which straps fit — common widths are 18, 20 and 22 mm.
How this is calculated
Case diameter is suggested from wrist circumference using common watch-fitting bands (slim wrists ~34–38 mm, average ~38–42 mm, larger ~42–46 mm+). Strap length is your wrist circumference plus about 2 cm of comfort; lug width scales with case size. These are guides — case size is partly personal taste.
Sources: Common watch-fitting guidance (case diameter by wrist circumference), cross-checked 2026.