How to Change a Watch Strap

Changing a watch strap is a five-minute job with one inexpensive tool, and the only part that can go wrong is buying the wrong width. Measure the gap between the lugs in millimetres, buy a strap in that exact size, compress the spring bar at each end and swap. If the watch has quick-release spring bars — a small lever you can see from underneath — you do not even need the tool.

One exception to deal with before anything else: a watch with an integrated bracelet cannot take a strap at all. The bracelet is shaped into the case rather than fitted between two lugs, so there is nothing to measure and nothing to fit. The Tissot PRX is the example in our own registry, and it is worth knowing before you buy a strap as a present for one.

Lug width is the only measurement that matters

The lug widthis the distance between the inside faces of the two lugs, measured in millimetres at the point where the strap meets the case. A strap that is 1mm too wide will not go in; one that is 1mm too narrow rattles and looks wrong. Common sizes are 18mm, 20mm and 22mm, and narrow women’s watches run much smaller.

Some listings publish the figure and most do not. Of the watches we track, these publish theirs, which spans most of the range you will meet:

If the listing does not state it, measure the old strap rather than guessing from the case diameter — there is no reliable ratio between the two. A cheap plastic ruler against the strap end is accurate enough; you are distinguishing 20mm from 22mm, not working to a tenth of a millimetre.

What you need, and what you do not

• A spring bar tool. A small handle with a forked tip at one end and a point at the other. It costs very little and it is the only tool required. Aftermarket straps often include one in the packet.
• A towel. Face-down on something soft protects the crystal and catches a spring bar if it pings loose. Spring bars are small, springy and very good at disappearing into carpet.
• Not a kitchen knife, a screwdriver or a nail. This is how lugs get scratched, and a scratch beside the lug is permanent and visible forever. The whole reason to spend a few dollars on the correct tool is that its fork sits around the spring bar rather than slipping off it into the case.

The seven steps

The step-by-step list is published with this page in a structured format, and here it is in prose. Measure the lug width. Lay the watch face-down on a cloth. Check underneath for a quick-release lever — if there is one, pull it sideways with a fingernail and skip to the end. Otherwise slide the forked tip of the tool between the strap and the inside of the lug, find the shoulder of the spring bar and press it inward. With the bar compressed, swing the strap away from the case until the bar clears the hole. Thread the bar through the new strap’s loop, seat one tip in one lug hole, compress the other and let it spring home. Then pull firmly on both halves: if either moves, the bar is not seated, and a bar that is not seated will let go at some point when you are not watching.

Two details people get wrong the first time. The buckle half goes on the 12 o’clock side, so the tail of the strap runs the right way around the wrist. And on a slip-through strap— a NATO or the fabric strap on a Timex Weekender — there is nothing to compress at all: the strap passes underneath the watch and threads through both bars, which is why those are the easiest straps in the world to change and why the watch sits a millimetre or two higher on the wrist. Our NATO versus leather comparison covers the trade-offs between the two styles.

Three watches that make this easy

A strap change is simplest on a watch that publishes its lug width and comes on a strap rather than a bracelet. These three do both, and the first does it without a tool.

A note on what we will not do here. We hold no verified replacement-strap listing, so this site names no aftermarket strap brand — recommending one would mean recommending something we have not checked, which is the one thing we do not do. Buy a strap from a seller with a returns policy, in the exact width, and the rest of this page tells you how to fit it. If a watch-plus-strap pairing is what you are actually shopping for as a gift, our watch and strap guide covers how to make that work, and our leather strap picks are the watches worth building it around.

Choosing what to put on instead

Once you can take a strap off, the question becomes which construction to fit. There are six worth knowing — solid-link and jubilee-style bracelets, woven steel mesh, leather, the nylon family (NATO, slip-through and perlon), and resin or rubber — each paired with one of four clasps, and only one of those combinations adjusts to any wrist without a tool. Our band-types guide sets out all of them with the ownership trade-offs and the lug-width warning.