If you've been shopping for a watch online, you've probably seen the advice: "Small wrists should wear small watches; large wrists can wear anything." It's true enough, but it skips the only question that actually matters — what's your wrist measurement, in millimetres, right now?
Everything else — case size, strap length, whether a bracelet overhangs the wrist bone — flows from that single number. And most people get it wrong because they guess.
What you need
Either of the following works:
- A flexible fabric or plastic tape measure (the kind a tailor uses)
- Or, if you don't have one, a strip of paper or string and a ruler
Don't use a rigid metal ruler on its own — your wrist is a compound curve, and a straight edge will always underestimate by 3–6mm.
Fig. 02 — A 170mm wrist with a 26mm case. Balanced fit.
The three steps
1. Wrap, just past the wrist bone
Wrap the tape or paper around your wrist where a watch naturally sits — about one centimetre toward your hand from the wrist bone (the bump on the thumb-side of your wrist). This is the narrowest part of your wrist, and it's where your watch will actually rest when you wear it.
Measuring further up the arm, even by a few centimetres, will give you a number that's too large. Your strap will be too loose, and your watch will rotate to the underside of your wrist within an hour.
2. Leave room for one finger
This is the step most people skip. Don't pull the tape tight against your skin — leave just enough room to slip the tip of your index finger between the tape and your wrist. That's the comfort gap: tight enough to stay in place, loose enough for your wrist to breathe and expand through the day (your wrist swells ~3–5% in warm weather or after exercise).
If you measure snug-to-skin and buy a strap at exactly that length, you'll spend half the summer loosening the clasp.
3. Read the number in millimetres
If you're using a tape, read directly off the scale. If you're using paper or string, mark where it meets itself, lay it flat, and measure against a ruler. Most watch brands size in millimetres, so write it down that way — a 170mm wrist is not the same conversation as a "medium."
Your wrist measurement is a number, not an adjective. Every size chart in the industry starts with that number — and most mistakes start with skipping it.
What your number actually means
Most adult wrists fall between 140 and 210mm in circumference. Here's roughly how that maps to case sizes, using the Fifth Studio range as an example:
- 140–160mm — slim wrists. A 26mm rectangle or 34–36mm round reads proportionally. Larger cases will overhang.
- 160–175mm — the balanced middle. Most round cases from 36–40mm sit well. Rectangles read dressy and intentional.
- 175–195mm — confident wearers of 40–42mm rounds. Smaller cases read as deliberate style, not accident.
- 195mm+ — larger wrists. 41mm and up wears best; anything under 36mm will read as "dressy on purpose."
A note on bracelet vs. strap
A bracelet has a small but real amount of rigidity: it adds roughly 2–3mm to the effective "wear length" because it can't flex as tightly as leather. If you're between sizes, a leather strap will typically read slightly smaller than a metal bracelet with the same measurement.
This is why most luxury brands, including ours, ship bracelets with removable links — so the rigidity-for-comfort trade-off can be tuned to your exact wrist rather than handed to you as a fixed number.
The three-minute version
If you skimmed to the bottom, here's the whole article in four lines:
- Wrap a tape measure just past the wrist bone, toward the hand.
- Leave room for one finger between tape and skin.
- Read the number in millimetres.
- Use it as your starting point for everything — case size, strap length, bracelet links.
The rest is just choice.
