Buying the perfect watch strap starts with one simple number: lug width. If you get this wrong, the strap won’t fit—no matter how beautiful or well-made it is.
The good news? Measuring lug width is quick and easy when you know what to look for. Here’s exactly how to measure it correctly.
What Is Lug Width?
Lug width is the distance (in millimeters) between the two lugs of your watch—the points where the strap attaches to the case.
This measurement determines the strap width you need. For example:
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20mm lug width = 20mm strap
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22mm lug width = 22mm strap
It must match exactly. There is no rounding up or down.
Method 1: Check the Manufacturer’s Specs (Easiest)
Many brands list lug width on their website or product page.
Search:
“Your Watch Model + lug width”
Example:
“Omega Seamaster lug width”
This is the simplest and most accurate method if the information is available.
Method 2: Measure with a Ruler (Quick & Basic)
If you don’t have calipers, you can use a metric ruler.
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Remove your current strap.
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Measure the inside distance between the lugs.
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Measure in millimeters (not inches).
Common sizes:
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18mm
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19mm
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20mm
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21mm
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22mm
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24mm
⚠️ Avoid guessing. Even 1mm off will not fit properly.
Method 3: Use Digital Calipers (Most Accurate)
For precision, digital calipers are ideal.
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Remove the strap.
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Place calipers inside the lugs.
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Read the measurement in millimeters.
This is the most reliable method—especially for higher-end watches.
Common Lug Width Sizes
Here are the most common sizes you’ll encounter:
| Watch Type | Typical Lug Width |
|---|---|
| Dress Watches | 18–20mm |
| Sports Watches | 20–22mm |
| Larger Dive Watches | 22–24mm |
Always confirm your specific model.
Don’t Forget Taper
Lug width is only the first measurement.
Many straps taper toward the buckle. A standard taper is 2mm, for example:
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20mm at the lugs → 18mm at the buckle
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22mm at the lugs → 20mm at the buckle
Taper affects the look and comfort but does not change the lug measurement.
Quick Release vs Standard Spring Bars
Once you know your lug width, you can choose:
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Quick-release straps for easy swapping without tools
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Standard spring bar straps for traditional installation
Both require the correct lug width to fit securely.
Final Thoughts
Measuring your lug width correctly ensures:
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Proper fit
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Clean alignment
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Secure installation
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No return headaches
Before ordering a new strap, take 60 seconds to confirm your lug width. It’s the simplest way to guarantee the perfect fit.