How to measure your watch lug width

What lug width is and why it matters

When you want to change the strap on your watch, you must find its lug width. The lugs are the metal horns that extend from the watch case to hold the strap in place. The lug width is the distance between the inside faces of the two lugs. This is the only size that determines if a new strap will fit your watch. If you get this measurement wrong, the strap will either not fit into the gap at all or will slide around. We match our straps by this exact size to ensure a secure fit for your favourite timepiece.

How to measure with a ruler or calipers

To measure your watch, place it flat on a table on a soft cloth to prevent scratching. Follow these steps to measure the gap:

• Align the zero mark of your metric ruler with the inside face of one lug.
• Read the millimetres to the opposite inside face of the other lug.
• Check the measurement twice to ensure accuracy.

Common watch lug sizes and odd widths

Most modern watches have standard lug widths. A width of 20 mm is highly common, representing 28 percent of watches. Another frequent size is 22 mm, which accounts for 20 percent. Some watch brands use odd widths or half sizes. We stock a wide range of options for these standard sizes so you can find your favourite colour. Having the correct measurement ensures that your chosen strap aligns with the watch case.

Alternative ways to find the width

If you do not have a ruler, you can often find the width written on the back of your existing strap. Turn the watch over and look for a small number stamped into the leather or rubber near the buckle or the watch case. This number represents the width in millimetres. Alternatively, you can search for the model reference number of your watch online. Manufacturers list the technical specifications of their watches, including the lug width, on their official websites. This is a reliable way to verify your measurement before making a purchase.

What happens if the strap is the wrong size

Choosing the correct size is essential for security. A strap that is 0.5 millimetres narrower than your lug width will still fit, but it can slide sideways. This movement exposes the spring bar, which might catch on clothing and release the watch from your wrist. Conversely, a strap that is wider than the lug gap will not enter the lugs at all. Leather and rubber straps cannot be squeezed into a smaller space without damaging the material. Buying the exact size prevents these issues.

How to change your strap easily

Once you have measured your watch, you are ready to swap the strap. Traditional straps require a spring bar tool to compress the spring and release the strap from the lugs. Work from the back of the watch to prevent visible scratches on the front of the lugs. Many modern straps now feature quick-release spring bars. These bars have a tiny lever on the underside, allowing you to install or remove the strap with your fingers, making the process completely tool-free. This makes changing your watch style a simple task.

Finding your next watch strap

Now that you know how to measure your watch, you can browse our collection with confidence. If your measurement is 18 mm, we have 435 options available. Select your size from our menu to view the colours and materials that will fit your watch. Buying the correct width first time saves you the trouble of returning a strap and ensures your watch remains secure on your wrist.