Replacing a Watch Band Yourself: Lug Width, Attachment and Length in Three Measurements

Written by the IMPERVORA team (IMPERVORA is an online jewelry retailer). Drafted with AI assistance and fact-checked against our published product and policy pages.

Replacing a tired or broken strap is an easy fix for a watch you love, and an easy one to get wrong. A band one millimeter too wide will not fit between the lugs, and one millimeter too narrow shifts sideways and looks loose. If the attachment is wrong, the band cannot be fitted at all.

Three measurements settle almost every case: lug width, attachment type and length. Below is how to take each one, and what to check before you order.

Measurement 1: Lug width

Lugs are the four short arms that extend from the watch case and hold the band. Lug width is the inside distance between the two lugs at one end of the case, in millimeters. It is the most important number for a replacement band, and there is no slack in it: choose the width that matches exactly.

How to measure it at home:

• Check the old strap first. Many straps have the width printed on the back near the lug end, often as a single number such as 20.
• Use calipers if you have them, measuring straight across between the inside faces of the lugs.
• Or use a millimeter ruler, held across the gap with the watch face up. Repeat two or three times.
• Measure the strap end, too. Where the strap meets the case, its width should match the lug width.

Two mistakes are common. One is measuring the outside of the lugs, which includes their thickness and is always too large. The other is choosing by case diameter: two watches with the same case size can have different lug widths. Odd widths such as 19 mm and 21 mm exist, so do not assume an even number. If you only have an inch ruler, 1 inch is exactly 25.4 mm, but a metric ruler will be far more accurate.

Measurement 2: How the band attaches

Width gets the band between the lugs. The attachment method decides whether it can be fitted.

• Standard spring bars. A spring-loaded bar runs through the end of the strap and clicks into small holes on the inside of each lug. You will usually need a spring-bar tool.
• Quick-release. Spring bars with a small built-in lever, so no tool is needed.
• Pass-through (one-piece). A single strap threads under the watch. Check there is enough clearance under the case for the strap's thickness. This is also the usual option for watches with fixed bars that cannot be removed.
• Expansion and link bracelets. Adjustable end pieces fit between the lugs on spring bars; check the lug-width range the end pieces fit.

On IMPERVORA's bands, spring bars are not listed as included, except on listings marked quick-release. You can reuse the bars from your current strap if they are in good condition, but a bar that no longer springs back firmly can let the watch drop. When in doubt, fit a new pair sized to your lug width.

Measurement 3: Length

The most reliable way to choose length is to measure what already fits. Lay your current band flat and measure it end to end, adding both pieces together for a two-piece strap. Then pick the closest listed length.

On our Etsy listings, length is stated as Short, Regular or Long, with the measurement in inches, and for two-piece straps that figure is the combined length of both pieces, not counting the watch case. On a band that fits well, the buckle pin usually lands near the middle holes, leaving room to adjust. Mesh bands adjust with a sliding clasp, and expansion bracelets stretch, so length matters less for those.

Taper and buckle width

Many two-piece leather straps narrow, or taper, from the lug end toward the buckle. A strap might be 20 mm at the case and narrower at the buckle. If you plan to reuse a buckle you already own, its inside width must match the strap's buckle-end width, not its lug-end width.

Choosing a material for how you wear the watch

• Leather is classic and softens with wear. Keep it dry where possible, because water and sweat can mark it.
• Mesh is a slim metal weave with a sliding clasp.
• Nylon is light and casual, and often a pass-through style.
• Silicone is soft and easy to rinse, which suits active wear.
• Steel comes in durable link or expansion styles.

Fitting the new band safely

Work over a soft cloth on a table, never over a sink or a hard floor. With standard spring bars, compress one end of the bar with the tool, ease the old strap out, then reverse the process with the new one until the bar clicks into its hole. Afterwards, give each end a gentle tug and check that both bar ends are seated. If you are not comfortable doing this, a local watch repairer can fit a band quickly.

A checklist before you order

1. Lug width in millimeters, measured inside the lugs.
2. Attachment type: spring bars, quick-release, pass-through or bracelet end pieces.
3. Spring bars: reuse, replace, or choose a quick-release listing.
4. Length, measured from a band that already fits.
5. Buckle-end width if reusing a buckle.
6. Material suited to how you wear the watch.

About IMPERVORA's bands

Our replacement bands are part of our supplies range and are sold through the IMPERVORA Etsy shop, in widths from 6 mm to 24 mm (most are 10 mm to 24 mm), in leather, mesh, nylon, silicone and steel. They are commercially made supplies, not made for any particular watch brand, and they are not for smartwatches.

Next step

For the full reference, including a table of attachment types and common fitting mistakes, read our Watch Lug Width and Replacement Band Guide and keep the short checklist in our Watch Band Size Guide beside you. You can read about the whole supplies range on our jewelry-making supplies page, explore impervora.com, or email Concierge@impervora.com if your measurement falls between two sizes; we reply within one business day.