Underdial
To change a watch strap, use a spring bar tool (or a thin flathead screwdriver) to compress the spring bar on one side, slide it free of the lug hole, and repeat on the other side. Reattach the new strap by compressing the spring bar, seating one end in the lug, then snapping the other side in. Takes under five minutes.
Swapping a watch strap is one of the most satisfying things you can do as a watch owner, and one of the most Googled tasks beginners put off far longer than they need to. The good news: with a $10 spring bar tool and five minutes, you can give any watch a completely different character without touching a watchmaker. Here’s the full process, common mistakes, and what to watch out for.
A question we hear often: the spring bar tool question is the one that holds most people back from swapping straps themselves.
The right tool is a spring bar tool, sometimes called a strap-changing tool. One end has a forked tip for pushing spring bars inward; the other usually has a pointed pin for screwing pin-buckle straps. They cost between $5 and $20, with the Bergeon 6767 (around $18) being the standard recommendation in the watch community. A cheap Chinese knockoff from Amazon at $5-$8 works fine for occasional use.
Can you use a thin flathead jeweler’s screwdriver instead? Technically yes, but the risk of the tool slipping and gouging your case lugs is real, especially on polished steel. If the watch cost you $300 or more, spend the $10 on a proper tool. Work on a soft surface, a folded microfiber cloth or a mousepad, so that if anything does slip, it lands on something forgiving rather than your case flanks.
One important nuance: some watches use quick-release spring bars, which have a small lever you pull with your fingernail rather than a tool. Brands like Tissot and Frederique Constant have standardized this on several models. If your strap has a small flush tab on the inside near each lug, you have quick-release bars. No tool required at all.
Here’s the complete removal sequence for a standard two-piece leather or rubber strap with conventional spring bars:
Step 1 — Secure the watch. Lay it face-down on a soft surface. Hold it steady with your non-dominant hand, or rest it in a watch cushion.
Step 2 — Locate the spring bar notch. Look at the inside edge of the lug (the metal “arms” extending from the case). You’ll see a small slot or dimple. That’s where the spring bar tip sits.
Step 3 — Compress the spring bar. Insert the forked tip of your spring bar tool into that notch and press inward, compressing the spring bar so it retracts slightly from the lug hole.
Step 4 — Pop the strap free. While holding the bar compressed, angle the strap away from the lug with your thumb. The compressed bar will clear the hole and the strap will come free on that side.
Step 5 — Repeat on the opposite lug. The spring bar will slide out with the strap still attached. Set both aside.
Step 6 — Remove the spring bars from the old strap (if you’re reusing them) or discard them if the new strap came with its own. Most replacement straps, especially those from aftermarket brands, include two spring bars in the package.
The whole removal takes under 90 seconds once you’ve got the feel of it.
This one comes up a lot: the reattachment step is where most beginners get frustrated. The spring bar always seems to pop out at the wrong moment.
Here’s the trick: seat one end first, then compress and snap the other. Specifically:
You’ll hear and feel a small “click” when each side seats correctly. If the strap feels loose or moves side-to-side more than a half-millimeter, the spring bar isn’t fully seated. Compress it again and reseat. A properly installed spring bar should have zero lateral play.
Pro tip: work with moderate light so you can actually see the lug holes. Squinting at a dark lug gap is how tools slip.
Before you order a replacement strap, you need three measurements. Get these right and any strap will fit; miss them and you’ll be returning orders.
| Measurement | What it is | How to find it |
|---|---|---|
| Lug width | Gap between lugs in mm | Measure with calipers, or check specs |
| Strap length | Total combined strap length | Match your wrist circumference (see below) |
| Taper | Whether the strap narrows from lug to buckle | Shown as e.g. “20/18mm” (lug/tail width) |
Lug width is the critical one. Common sizes are 18mm, 19mm, 20mm, and 22mm, with 20mm being the most common on watches in the 38-42mm case range. Standard strap lengths run roughly 165-180mm for women and 184-197mm for men, though this varies by brand. If your wrist is under 6.5 inches, look for a “short” strap; above 7.25 inches, go “long.”
Strap length is presented as two numbers (e.g., 125/75mm), where the first, always larger, is the tail (hole) side and the second is the buckle side. If your existing strap fits well, just measure it before you remove it and match those numbers.
For more on lug width and how it affects fit, see our watch lug width guide.
Readers frequently ask: whether rubber, leather, NATO, and mesh straps all work the same way.
Leather and rubber straps use standard spring bars and follow the process above exactly.
NATO straps are different. They thread through the spring bars rather than attaching to them, which means you don’t need to remove the spring bars at all. Slide the strap under the existing bars, thread through the keeper loops, and you’re done. NATO straps are the fastest possible swap and require no tools whatsoever if your spring bars are already installed.
Mesh (Milanese) and metal bracelets mostly use spring bars too, but the bars often sit inside the end link rather than being visible from the outside. The technique is identical, compress, clear, snap, but you may need the pointed pin end of your tool to get into the tighter space inside a metal end link. Some integrated bracelets (like those on the Tissot PRX or Citizen Tsuyosa) use a proprietary pin system; in those cases, check the brand’s instructions or contact an authorized dealer, as forcing them can damage the bracelet.
Spring bars do wear out, but not quickly. A quality spring bar rated for regular use can handle hundreds of swaps. If you’re rotating straps weekly, plan to inspect your spring bars every year or two and replace them proactively. A set of ten generic spring bars in the right diameter costs about $3-$5. Cheap insurance.
Signs a spring bar needs replacing: visible corrosion, a bent or deformed tip, or a bar that no longer clicks firmly into the lug holes. Never ignore a bar that feels loose. A failed spring bar means your watch ends up on the floor.
Watch industry guidance generally suggests that stainless steel spring bars of 1.5mm diameter or larger are appropriate for everyday wear watches; thinner 1.2mm bars (common on fashion and dress watches) should be treated more carefully and not used with heavier metal bracelets.
If you wear the same watch daily and rotate straps frequently, keeping a small container of spare spring bars in your watch drawer is sensible practice. Tools like Underdial can help you track which watches are in rotation and flag when a strap swap might make sense, for instance, surfacing a rubber option for a dive watch you’re wearing on the wrong band.
The most common mistakes in a strap swap, ranked by how often they happen:
1. Spring bar flying across the room. Happens when the bar launches out of the lug before you’re ready. Fix: always have one side already seated before compressing the other. Work over a light-colored cloth so you can find the bar quickly if it does escape.
2. Scratching the case. Caused by the tool tip slipping off the spring bar notch and dragging across polished steel. Fix: use the forked tip (not the pin), work slowly, and keep the fork flush against the lug face.
3. Wrong strap size ordered. The watch’s case diameter is not the same as the lug width. A 42mm watch can have an 18mm, 20mm, or 22mm lug. There’s no universal rule. Always measure before ordering.
4. Installing the strap upside down. Leather straps typically have a smooth outside and a rougher or stamped inside. Rubber dive straps often have the texture on the outer face. Double-check orientation before seating the second spring bar.
5. Spring bar not fully clicked in. Feels secure but wobbles slightly. A strap that isn’t fully seated can detach under normal movement. Always tug gently on both sides of the strap after installation to confirm full engagement.
Do I need a special tool to change a watch strap? A spring bar tool is strongly recommended. It costs $5-$15 and protects your case from scratches. In a pinch, a thin flathead jeweler’s screwdriver works, but there’s more risk of slipping and marring the case.
Can I change a watch strap without scratching the case? Yes. Use a proper spring bar tool and work on a soft surface like a microfiber cloth or mousepad. Apply steady, controlled pressure rather than force, and keep the tool tip seated firmly in the spring bar notch at all times.
How do I know what size strap to buy? Measure the lug width, the gap between your watch’s lugs where the strap attaches, in millimeters. Common sizes are 18mm, 20mm, and 22mm. This number is often printed on the original strap or in the watch’s spec sheet. Our watch lug width guide covers this in detail.
How do I change a watch bracelet (metal) instead of a strap? Most metal bracelets use the same spring bar system as straps. A few use screws or fixed bars, which require a small screwdriver or the brand’s proprietary tool. Check the bracelet end links: if you see a small notch or hole, it’s spring bar. If you see a screw head, it’s a fixed system.
How long does it take to change a watch strap? Once you’ve done it two or three times, the whole swap takes under two minutes per strap. Your very first attempt might take 5-10 minutes as you get a feel for spring bar tension. There’s no need to visit a jeweler for a basic strap change.
Do I need a special tool to change a watch strap?
A spring bar tool is strongly recommended, it costs $5, $15 and protects your case from scratches. In a pinch, a thin flathead jeweler's screwdriver works, but there's more risk of slipping and marring the case.
Can I change a watch strap without scratching the case?
Yes. Use a proper spring bar tool and work on a soft surface like a microfiber cloth or mousepad. Apply steady, controlled pressure rather than force, and keep the tool tip seated firmly in the spring bar notch at all times.
How do I know what size strap to buy?
Measure the lug width, the gap between your watch's lugs where the strap attaches, in millimeters. Common sizes are 18mm, 20mm, and 22mm. This number is often printed on the original strap or in the watch's spec sheet. Our watch lug width guide covers this in detail.
How do I change a watch bracelet (metal) instead of a strap?
Most metal bracelets use the same spring bar system as straps. A few use screws or fixed bars, those require a small screwdriver or the brand's proprietary tool. Check the bracelet end links: if you see a small notch or hole, it's spring bar. If you see a screw head, it's a fixed system.
How long does it take to change a watch strap?
Once you've done it two or three times, the whole swap takes under two minutes per strap. Your very first attempt might take 5, 10 minutes as you get a feel for spring bar tension. There is no need to visit a jeweler for a basic strap change.