How to Cut Your Rubber Watch Strap to Size

Cut-to-size rubber straps are a great way to get a perfect, tailored fit — but we know the idea of taking scissors to a brand-new strap can feel daunting. The good news? With a few simple tools, a careful approach, and a little patience, it’s a straightforward process that anyone can do at home.

In this guide, I’ll walk you through exactly how to measure, mark, and cut your strap for the best fit. I’ll be demonstrating with four of our bestselling WatchGecko Rubber straps, but the methods work for almost any cut-to-size rubber strap — even those from other brands (though we’ll pretend not to notice).

Before you start, gather your tools:

• Scissors (sharp kitchen scissors will work)
• Craft knife or Stanley knife (for cleaner cuts)
• Cutting mat or chopping board
• Ruler or measuring tape (millimetres are best)
• Wrist measurer (or a soft measuring tape)
• Spring bar tool (or a small flat tool)
• Tape (masking tape works well)

Optional but helpful: a metal ruler for guiding straight cuts, and a steady surface with good lighting.

• Mosaic CTS Rubber Watch Strap
• WatchGecko Sedona CTS Rubber Deployant Watch Strap
• WatchGecko 400 Italian Rubber Divers Reversible Watch Strap
• Radius CTS Rubber Watch Strap

Wrap your wrist measurer or tape measure around the point where you normally wear your watch. Note the measurement in millimetres for the best accuracy.

For example, my wrist is 175 mm. To give myself a bit of tolerance, I add 10mm, making it 185mm. This extra allowance means you can fine-tune the fit later without the strap being too tight.

Now measure your watch’s lug-to-lug distance — from one spring bar hole across the case to the other.

• Make sure you measure between the spring bar holes (not the ends of the lugs).

My Seiko Willard measures 40 mm lug-to-lug. Write yours down.

Measure your clasp length from end to end. Most of our deployant clasps are 20 mm, but check yours, especially if it’s from another brand.

Write this down too.

Here’s the simple formula:

Wrist size + tolerance – (lug-to-lug + clasp length) ÷ 2 = strap length per side

Using my example:

185 mm – (40 mm + 20 mm) = 125 mm total strap length
125 mm ÷ 2 = 62.5 mm per side (I round up to 63 mm).

Using a ruler, measure from the spring bar end of the strap and mark your cut point with tape.

Tip: If your measurement falls between sizes, cut to the longer size. You can always trim more later, but once you’ve cut, there’s no going back.

For straps with grooves (like Sedona, Radius, and Mosaic), cut along the groove just above your tape mark. For straps without grooves (like the 400), ensure your cut leaves enough material around the spring bar hole to keep it secure.

There are two main ways to cut your strap:

1. Craft knife method – Place your strap on a cutting mat or chopping board. Using a sharp craft knife, make a steady cut along your mark or groove. This gives the cleanest result.
2. Scissors method – Use sharp kitchen scissors for a quick and effective cut. Just take care to keep the cut straight, especially on straps without grooves.

Repeat on the other half of the strap.

• Insert the spring bars into the newly cut ends.
• For deployant clasps, start with the middle micro-adjustment hole so you can tighten or loosen later.
• Attach the other half of the strap to the buckle or clasp, then fit the strap to your watch case.

Put the watch on your wrist and see how it feels.

• If it’s slightly loose or tight, adjust the spring bar position within the clasp.
• If it’s too loose, you can remove another small section — but take off only one segment at a time and re-test.

If you’d rather skip the calculations, the Mosaic strap’s segmented design makes it easy to cut gradually:

• Remove one or two segments at a time.
• Try it on after each cut until you reach your ideal fit.

This method takes longer but greatly reduces the risk of cutting too much at once.

• Take your time. Rushing leads to mistakes.
• Always cut less than you think you need — you can remove more later.
• Keep your cuts neat for the best appearance and fit.
• Test the fit often during the process.

Once you’ve finished, you’ll have a strap that feels made-to-measure and looks just as good as it did before you cut it. Whether it’s for a diving trip or a day at the desk, you’ll enjoy a perfect, secure fit — and the satisfaction of having done it yourself.

If you prefer to follow along visually, you can also watch the full step-by-step demonstration on the WatchGecko YouTube channel.