Honest sourcing note: “Alligator” and “crocodile” are different species — true alligator is American (Alligator mississippiensis); most Indonesian/Asian straps are saltwater crocodile (Crocodylus porosus), the same luxury tier. We label species accurately and never sell embossed calf as exotic. Genuine crocodilian is CITES-regulated (typically Appendix II, farmed); international orders ship with documentation, and you are responsible for your country’s import rules — this is general information, not legal advice. Prices are indicative ranges (mid-2026); final pricing is by quote. We are an independent authority and sourcing desk and connect you to vetted makers.
How to measure watch strap size means knowing two things: your lug width and your strap length. To measure watch strap size correctly, you match the lug width of your watch head to the strap, then choose a length that fits your wrist and buckle style.
What “watch strap size” actually means
For practical strap buying, “size” has three separate parts:
- Lug width
- The distance between the lugs of your watch case, in millimetres. This is the most important number for fit.
- Strap length
- The total length of the two strap pieces (excluding the buckle), often written as something like 115/75 mm.
- Taper
- How much the strap narrows from the lugs down to the buckle or clasp (e.g., 20 → 16 mm).
If you only get one thing right: the strap’s lug width must match your watch’s lug width. Length and taper can be tuned to taste and wrist size.
How to measure lug width (the critical dimension)
You cannot measure lug width on the strap alone; you must measure the watch head between the lugs.
Tools you can use
Use one of the following, in order of accuracy:
- Digital or vernier calipers (best)
- Metric ruler with 0.5 mm markings
- A printable lug-width guide from a reputable source, printed at 100% scale
Step‑by‑step: measure lug width
- Remove the existing strap or bracelet if possible.
This exposes the full gap between the lugs and avoids measuring the old strap, which may be compressed or mis-sized. - Place the watch face up on a flat surface.
- Measure the inside distance between the lugs.
With calipers: gently close the jaws on the inner faces of the lugs.
With a ruler: align the 0 mark with the inner wall of one lug and read the measurement at the inner wall of the opposite lug. - Read the value in millimetres and round to the nearest whole millimetre.
Common lug widths (publicly documented for many brands):
- 16 mm – smaller dress watches, vintage pieces
- 18 mm – classic dress watches, many 34–36 mm cases
- 19 mm – some vintage and “in‑between” references
- 20 mm – very common modern “all‑rounder” size
- 21 mm – used by some big Swiss brands on flagship models
- 22 mm – typical for larger sports and dive watches
If your measuring tool gives you, for example, 19.3 mm, your lug width is effectively 19 mm. Manufacturers design cases around full‑millimetre increments.
Why lug width must match exactly
A strap that is too narrow (e.g., 19 mm strap in a 20 mm lug):
- Leaves a visible gap; looks wrong on high‑end pieces.
- Allows more movement of spring bars; more wear and potential failure points.
A strap that is too wide (e.g., 21 mm strap forced into a 20 mm lug):
- Can warp or mark the strap at the ends.
- Makes spring bar installation unsafe or impossible.
For exotic skins such as American alligator and Crocodylus porosus (saltwater crocodile), forcing the lug fit can cause permanent edge damage. Correct lug width is non‑negotiable.
How to measure strap length for your wrist
The second part of how to measure watch strap size is understanding how long the two pieces should be. Standard strap length is written as:
long side / short side (in mm)
—for example, 115/75 mm.
Key measurement: your wrist circumference
You will need your actual wrist size:
- Wrap a soft measuring tape around the part of your wrist where the watch sits.
No tape? Use a strip of paper or string, mark the overlap, then measure that against a ruler. - Record the result in centimetres or millimetres.
As a rough guide:
- 14–15 cm wrist ≈ 5.5–6.0 inches (small)
- 16–17 cm wrist ≈ 6.25–6.75 inches (average‑small)
- 17–18.5 cm wrist ≈ 6.75–7.25 inches (average)
- 19–20 cm wrist ≈ 7.5–8.0 inches (large)
Reading strap length numbers
Example: 115/75 mm
- 115 mm = long side (the side with holes)
- 75 mm = short side (the side with buckle, excluding the buckle itself)
Total effective length of the strap is roughly:
strap length + watch head length
The watch head (lug‑to‑lug length) usually adds 45–52 mm for many classic watches; large sports pieces can add more.
Standard lengths vs wrist sizes
The table below gives ballpark matches of “off‑the‑shelf” lengths to wrist sizes. These are general watch‑industry norms; case size, lug shape, and how tight you prefer the strap all affect this.
| Strap length (mm) | Common label | Approx. wrist circumference |
|---|---|---|
| 105 / 65 | Extra‑short | ~14–15 cm |
| 110 / 70 | Short | ~15–16.5 cm |
| 115 / 75 | Standard | ~16–18 cm |
| 120 / 80 | Long | ~18–19.5 cm |
| 125 / 85 | Extra‑long | ~19.5–21 cm |
These figures are starting points. Hand shape, watch case length, and how far from the wrist your watch sits can shift your ideal by a size.
How to estimate your ideal length at home
If your current strap fits you well, measure it:
- Remove the strap from the watch.
- Measure from the lug end to the tip of the long piece.
- Measure from the lug end to the middle of the buckle pin on the short piece (or to the end if you will reuse the same buckle).
- Write it as “long / short” in mm.
That is your reference length. When ordering a new strap, you can repeat that size or adjust by 5 mm up or down if you want the buckle to sit more centred on the underside of your wrist.
If you do not have a strap that fits properly, an accurate lug‑to‑lug dimension of your watch plus your wrist circumference will allow a custom shop to calculate a length that places the buckle where it should be.
Understanding taper: lug width vs buckle width
Taper is often overlooked in “how to measure watch strap size” guides, but it matters for both comfort and aesthetics.
- No taper – 20/20 mm: same width at the lugs and buckle; more tool‑watch or modern‑sport look.
- Moderate taper – 20/18 mm, 21/18 mm: common on many OEM straps; balances presence and comfort.
- Dress taper – e.g., 20/16 mm, 19/16 mm: gives a more elegant profile, especially for alligator.
If you are reusing a deployant clasp or branded pin buckle, measure the inside width of that clasp or buckle. That is your target buckle‑end width.
Example:
Your watch has 21 mm lugs, and your OEM deployant is 18 mm internally. Your strap spec will be 21/18 mm, and any custom or aftermarket strap must follow that taper for the clasp to fit correctly.
How strap thickness and construction affect fit
Length and width are not the full story. Thickness has a significant impact on both comfort and compatibility with your watch.
Typical thickness ranges
For leather straps, these thickness ranges are typical:
- Dress watch straps: ~2.0–3.0 mm
- Everyday/all‑rounder straps: ~2.5–3.5 mm
- Sport straps for larger watches: ~3.5–5.0 mm
For American alligator or saltwater crocodile (Crocodylus porosus), the hide itself dictates how thin you can go before compromising durability. Belly cuts tend to allow cleaner, more consistent thinning than flank.
Case and clasp compatibility
You should check:
- Spring bar clearance – Some watches, especially slim dress pieces, have little vertical space between the case and spring bar. A strap that is too thick at the lug end may not fit.
- Deployant clasp spec – Many deployants are designed for a certain max thickness at the fold. Too thick, and the clasp won’t close properly.
If you are having a strap custom made, provide:
- Your watch model and lug width.
- Whether you are using a pin buckle or a deployant clasp.
- Any thickness limitations you already know (for example, if a previous strap was too thick to articulate freely).
Species, cuts and grading: why precision matters
Alligator Watch Straps specialises in exotic skins for collectors who care about correct species labelling and legal sourcing. Getting your size right is part of that, but so is choosing the right material and grade.
American alligator vs Crocodylus porosus
We use species names accurately:
- American alligator (Alligator mississippiensis) – What most high‑end Swiss brands mean by “alligator” on their spec sheets.
- Crocodylus porosus – Often called “porosus” or “saltwater crocodile” in the trade. Not the same animal as American alligator.
We do not re‑label one as the other. If a strap blank is American alligator belly, it is sold as such. If it is C. porosus flank, it is labelled crocodile, not alligator.
Common strap cuts and grades for exotics
Different cuts and grain areas affect both look and price. Here is a factual summary relevant to sizing and specification:
| Spec | Typical options | Impact on sizing/feel |
|---|---|---|
| Cut area | Belly, tail, flank | Belly gives more uniform, flatter scales for dress tapers; flank/tail can be stiffer, affecting how the strap curves on smaller wrists. |
| Scale pattern | Large‑scale, medium‑scale, small‑scale | Larger scales on wider lug widths (20–22 mm); small‑scale better for narrow lugs (16–18 mm) to avoid partial scales at the edge. |
| Grading | High grade (fewer defects) vs commercial grade | Higher grades allow cleaner cuts for very narrow lugs and aggressive tapers without visible imperfections. |
| Lining leather | Calf, goat, rubber‑backed | Thickness and flexibility of the lining change how a given length feels on the wrist. |
CITES and legality (not legal advice)
Both American alligator and Crocodylus porosus are covered under CITES (Convention on International Trade in Endangered Species). In practice, that means:
- Legally exported skins and finished straps require correct CITES documentation.
- Import rules depend on the country, species, and whether the product is finished or raw.
- Some jurisdictions do not allow private import of certain reptile leathers at all.
We are not a law firm and cannot give legal advice. For cross‑border orders, we check current regulations for the destination and will tell you plainly if a given species/strap configuration is not suitable for shipping to your address.
If you have specific questions about a custom strap involving alligator or porosus and your country’s rules, use plan your trip with us by email or WhatsApp; we can share what we know and point you toward official resources.
Price ranges for exotic‑leather straps (last verified June 2026)
Prices vary with species, grade, cut, construction complexity, and order volume (single custom vs wholesale). For orientation only, and explicitly as ranges:
- American alligator, single custom strap
- Typically falls in the mid‑ to high‑hundreds of USD for a fully hand‑made, lined, stitched strap, depending on grade and finishing.
- Crocodylus porosus, single custom strap
- Often priced above comparable alligator due to skin cost and grading; end pricing varies with pattern selection and cut area.
- Wholesale / OEM runs
- Per‑strap costs can be significantly lower than single custom orders, depending on quantity and spec standardisation.
Exact quotes require a defined spec: lug width, taper, length, species, cut, lining, thickness, edge style, and stitch type. You can request that spec work and pricing via plan your trip, and our sourcing desk can follow up over WhatsApp if you prefer.
Brand‑specific fit: getting the measurements we actually need
For many modern watches, we already know the nominal lug widths. What we still need from you is:
- Wrist circumference (measured, not guessed).
- Preference for buckle vs deployant, and whether you are reusing an OEM component.
- Desired aesthetic: dress taper versus minimal taper, padded vs flat.
If your watch uses integrated or semi‑integrated straps (shaped ends that follow the case), this affects the strap design beyond simple width and length. Some models accept straight‑end straps; others do not. In borderline cases, clear photos of the watch head from the side and between the lugs are essential for assessing compatibility.
Quick checklist: how to measure watch strap size correctly
Use this as a concise, practical checklist:
- Measure lug width: inside the lugs, in mm. Do not guess from online specs if your case has been modified or if you’re between sizes.
- Measure your wrist: actual circumference, using tape or string + ruler.
- Note current strap length (if it fits well): record as long / short in mm.
- Decide on taper: confirm buckle/clasp width, then choose lug width → buckle width (e.g., 20 → 16 mm).
- Consider thickness: dress vs sport, and any known clearance limits at your lugs or clasp.
- Confirm species and cut if buying exotic: American alligator vs C. porosus; belly vs flank; scale size preferences.
From there, a custom shop can take you the rest of the way—patterning, lining choice, stitching, and finishing.
Working with Alligator Watch Straps on custom sizing
Alligator Watch Straps exists for collectors and trade buyers who want correct species, honest grading, and precise fitment—not marketing fiction.
For individual collectors:
- We help you translate your wrist and watch measurements into a precise spec (lug width, taper, length, thickness).
- We label species correctly (American alligator vs Crocodylus porosus) and will not downgrade or swap materials without telling you.
- We source and build to your spec through vetted partners; if you proceed with our partner they may pay us a referral fee at no extra cost to you.
For brands and retailers:
- We can assist with size runs that match your case line‑up (e.g., 18, 20, 21, 22 mm with corresponding standard/short/long lengths).
- We work with real measurements and pattern files, not just catalogue names like “XL” or “short”.
If you want help turning your measurements into a nailed‑on spec for American alligator or crocodile straps, plan your trip with us. You can include your wrist size, watch model, and any photos; we can continue the conversation by email or WhatsApp, whichever you prefer.
How do I measure lug width if I don’t have calipers?
Use a metric ruler with at least 1 mm markings. Remove the strap, place the zero mark against the inner side of one lug, and read the distance to the inner side of the opposite lug. Round to the nearest millimetre—manufacturers standardise lug widths to whole mm increments.
My wrist is 16 cm. What strap length should I choose?
For a typical 38–40 mm watch, a 16 cm wrist often works well with a “standard” 115/75 mm strap. If your watch is very small and you like a snug fit, 110/70 mm (short) can be better. Your existing strap—if it fits comfortably—is the best reference; measure it and match those numbers.
Can I use a 20 mm strap on a 19 mm lug?
No. Forcing a wider strap into a narrower lug risks damaging both the strap and the watch and makes spring bar installation unsafe. Always match lug width exactly: 19 mm strap for 19 mm lugs, 20 mm strap for 20 mm lugs, and so on.
How do I size a strap for a deployant clasp?
Measure lug width first, then measure the internal width of the deployant where the strap attaches; that is your buckle‑end width. Next, measure a strap that already works with that clasp, or provide your wrist circumference and watch model so a custom maker can calculate the right long/short lengths. Deployant straps often use a slightly shorter short side than pin‑buckle straps to centre the clasp under your wrist.
Is “genuine crocodile” automatically better than calf for small wrists?
Not automatically. For small wrists, the deciding factors are strap thickness, softness, and curvature. High‑quality American alligator or C. porosus, cut from appropriate belly sections and thinned correctly, can drape very well even on small wrists. A thick, heavily padded exotic strap can feel bulkier than a well‑made calf strap. Species alone does not guarantee comfort; construction and sizing matter just as much.