How to Measure Your Wrist for a Watch

Two numbers decide whether a watch fits you: circumference (around the wrist) and width (across the flat top of the wrist). Circumference takes 60 seconds with household items. Width takes 10 more.

1. Circumference, the 60-second version

Cut a strip of paper about 2 cm wide and long enough to wrap your wrist (a shoelace, charging cable, or piece of string works too).
Wrap it around your wrist just above the wrist bone, where a watch head actually sits, not further up the forearm.
Snug, not tight: you should be able to slide a finger under it. A watch worn at normal comfort has that same slack.
Mark where the paper overlaps itself, lay it flat, and measure the length to the mark with a ruler.
Note it in cm or inches. Average men land near 17-19 cm (6.7-7.5"); average women near 15-16.5 cm (6-6.5").

A soft tailor's tape is more accurate if you have one, follow the same placement rule: just above the bone, snug with one finger of slack.

2. Width, the 10-second upgrade

Rest your hand palm-down on a table, relaxed.
Hold a ruler flat across the top of your wrist, at the spot where the watch head sits.
Measure edge to edge, in mm. Typical range: 45-60 mm.

This is the number that lug-to-lug must not exceed, so it's worth the extra 10 seconds. If you skip it, the calculator estimates width from your circumference with a linear fit calibrated to published watch-size charts (width ≈ 0.292 × circumference); that's close enough for most people, less exact for very flat or very round wrists, who should measure the width directly.

3. Measure the watch, not just the wrist

When you're evaluating a specific watch, find its case diameter and lug-to-lug (also called lug height) from the manufacturer's spec page or a review. Lug-to-lug is the distance from the tip of the top lugs to the tip of the bottom lugs, the total length of the watch head. If a listing only shows diameter, search "<model> lug to lug mm" before buying; on watches under 40 mm the lugs often matter more than the case.

Common mistakes

Measuring over clothing or a bracelet. Adds 5-10 mm and ruins the recommendation. If the bracelet itself is what you are sizing, that is a separate job with its own allowance rules: the bracelet and bangle measuring guide covers it.
Measuring at the forearm. The watch sits above the bone; that's where the tape goes.
Pulling the tape tight. Compresses the wrist and underestimates by 3-5 mm.
Trusting "men's 40 mm" labels. Fit follows your wrist, not the marketing department; plenty of men are better served by 36-38 mm, and the chart shows why.

Got your numbers? Run them through the calculator or jump straight to the full size chart. No tape measure and no ruler in the house? The no-tape method covers calibration with coins and a printable strip. The same tape reading also settles bicep-band sizing if you wear a WHOOP: measure the fullest part of your upper arm and the WHOOP band size chart maps it to S/M or L/XL. It also settles Pixel Watch band sizes, which go by wrist circumference rather than any strap width: the Pixel Watch band size chart maps the reading to Active Band S/L or Gradient Stretch XS-XL. Samsung's Galaxy Fit3 works the same way: its official S/M and M/L band lengths are picked straight from the wrist reading, and the Galaxy Fit3 band size chart maps them.