You need a new watch strap. You've found one that you like and are ready to pull the trigger. But are you sure you're getting the right size?

Buying a watch band is different to pants or shoes, where you have to try them on for size. That's because a proper fit isn't just relative to your body but also your watch. Follow these simple tips to ensure the right fit.

Measure your watch's lug width

What width now? Those metal protrusions where the strap attaches — those are the lugs and the strap has to fit between them, so you'll need to determine that exact distance.

Lug width is the number-one most important measurement you'll need. Watch band sizes are almost always given in millimeters, and they refer to the width of the strap where it meets the watch, between the lugs. You can use a ruler, caliper or something like a soft tape measure.

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Luckily, most modern men's watches are of standard, even-numbered sizes like 18mm, 20mm and 22mm, but there are exceptions. Sometimes, the size will even be printed on the underside of your current strap, so you might want to check there first.

(Some strap makers also mention the width of the strap at its included buckle. Aside from noting whether or not the strap tapers, you don't need to worry about this unless you're an advanced strap collector who also plans on replacing the supplied buckle.)

unimatic watches lug diagram
Unimatic Watches

Measure your wrist size and determine the strap length you need

Although watch straps are typically adjustable to fit different wrist sizes, those that are too long or too short can still very much be an issue. Sure, you can add holes to a strap that's too long, but it's not ideal. If the strap maker offers different lengths, you want to be sure to know your wrist size and get the right one.

Break out your soft tape measure (or even download and print something from the internet). Take the measurement on the part of your wrist that you like to wear a watch, as it might be slightly different above or below the wrist bone. This number doesn't correspond exactly to strap lengths, and rather it provides a reference for general sizes.

Got a skinny wrist around the six-inch mark? Go for the shorter option. Girthily wristed individuals will want a longer one. Strap makers will usually provide some insight about what size wrist their straps will easily fit — but sometimes you have to look carefully for this information.

watch strap
Hunter D. Kelley

What about Apple Watch bands?

Like its software, Apple's Watch and bands are a closed ecosystem. There are two sizes of any given generation of Apple Watch, so all you have to do is know the size of the watch you have.

For those that offer different length options, follow the above advice to determine your size. Apple's "Solo Loop" style bands come in nine sizes, and Apple offers tools to determine your exact size.

The exception: integrated designs

An increasingly popular feature in watches are those with integrated bracelet or strap designs. These are watches with bands made specifically for them — and for which most aftermarket bands won't fit. For something like the Tissot PRX, for example, you'd need to order something from the brand itself or get one especially made. Check your watch first to make sure that it's designed to work with third-party straps.

Start shopping for a new strap with these great options