Passports & provenance
Maker's marks, serial numbers and QR codes for furniture
Updated · 7 min read
A maker's mark tells anyone who turns a chair over who made it. A serial number tells you which chair it is. Together they connect a physical piece to everything you know about it: the timber, the finish, the date, the repairs. For a studio making a few dozen pieces a year, that link is cheap to create at the bench and hard to recreate later.
This guide covers why to mark and number pieces, the common marking methods, where to put the mark, a numbering scheme that stays simple, and what we learned about sizing laser-engraved QR codes. The QR figures come from our own tests, and we say plainly which parts are still untested on real timber.
Key takeaways
- A maker's mark identifies the workshop, and a serial number identifies the individual piece and its records.
- A year-and-sequence scheme such as 2026-017 is easy to run and should never be changed once a number is issued.
- Marks belong on protected surfaces that will not be sanded, worn by use or hidden by later fixings.
- Laser-engraving guides commonly recommend QR modules of at least 0.5 mm (0.02 in), plus a quiet zone of four modules on every side.
- In our tests, an upper-case link without a query string produced a smaller QR code than the same link in mixed case.
- Our software tests decoded every code from 15 to 40 mm (0.6 to 1.6 in), but we have not yet tested physical engravings on oak, walnut or ash.
Why mark and number your pieces
Identification. A mark answers the question "who made this?" for the owner, for anyone they sell it to, and for you when a piece comes back years later.
Repairs. When a client calls about a split top or a loose joint, a serial number takes you straight to the species, finish and construction notes. Matching an oil or replacing a part is easier when you know exactly what was used.
Resale and history. A clear mark and a record of the piece give a future owner something concrete to go on. A certificate of authenticity that quotes the same serial number makes the link explicit.
Records you may need later. Proposed EU product rules link information to unique product identifiers. Nothing requires this for furniture yet, but numbering every piece now is a low-cost habit. Our guide to digital product passports for furniture sets out what is decided and what is not.
Ways to apply a maker's mark
| Method | Good for | Things to watch |
|---|---|---|
| Branding iron (electric or heated) | A consistent logo on solid timber | Needs even pressure and heat; scorches can vary with species and moisture |
| Steel stamps | Serial numbers and initials, struck into the wood | Crisp on dense hardwoods, softer on open-grained or soft timbers |
| Laser engraving | Logos, serials, small text and QR codes | Requires access to a laser; settings need testing per species and finish |
| Brass or steel plate | A durable, refinish-proof mark | Must be fixed securely; screws or pins should not split thin parts |
| NFC tag, as an optional extra | A tap-to-open link alongside a visible mark | Needs a phone with NFC; nearby metal can interfere, so on-metal tags exist for that case |
A visible mark is the core. An NFC tag can be a useful addition, but a phone has to support NFC to read it, and a tag hidden under a surface gives no visual cue that it is there. Treat it as a supplement to a printed serial and code, never a replacement.
Where to place the mark
Choose a spot that is protected from wear and unlikely to be sanded if the piece is ever refinished.
| Piece | Good locations |
|---|---|
| Dining or coffee table | Underside of the top near an apron, or inside an apron |
| Chair or stool | Underside of the seat, or inside a rail |
| Cabinet or sideboard | Inside a door, on a side panel inside the carcass, or on the back |
| Drawer unit | Drawer side or back, or inside the carcass |
| Bed | Inside a rail, near the headboard joint |
Avoid places where a fixing, a glue block or a later repair is likely to cover the mark. If the piece has a removable part, such as a drawer, mark the carcass as well so the record stays with the main body of the piece.
A simple numbering scheme
Use the year followed by a sequence number, padded to three digits: 2026-001, 2026-002, and so on. It sorts correctly, tells you roughly when a piece was made, and leaves room for more than enough pieces per year.
A few rules keep it trustworthy:
- Issue a number once. Never reuse or edit it. If a commission is cancelled, retire the number and note why.
- Keep the number free of personal data. The client's name lives in your records, not on the piece or in a public listing.
- Use one sequence for the studio. Separate series per product type add complexity without much benefit for a small workshop.
- Record the number before marking. Write it into your records first, then stamp or engrave it, so the record and the mark always agree.
Laser-engraved QR codes: what our tests showed
A QR code is a grid of square modules. The QR standard's developer, DENSO WAVE, states that a QR code needs a margin of four modules on all sides, called the quiet zone. Laser-engraving guidance commonly suggests modules at least 0.5 mm (0.02 in) wide; OMTech's guide is one example. The physical size of the code is therefore the number of modules, including the quiet zone, multiplied by the module size.
How many modules you need depends on what the code encodes. On 30 October 2026 we generated codes for two forms of the same link and measured the result.
| Encoded text | QR mode | Version and grid | With quiet zone | Smallest size at 0.5 mm modules |
|---|---|---|---|---|
https://studio-a.example.com/p/2026-017?s=qr |
Byte | Version 4, 33 × 33 | 41 × 41 | About 20.5 mm (0.81 in) |
HTTPS://STUDIO-A.EXAMPLE.COM/Q/2026-017 |
Alphanumeric | Version 3, 29 × 29 | 37 × 37 | About 18.5 mm (0.73 in) |
The second link is smaller because QR alphanumeric mode packs characters more tightly, but it only accepts upper-case letters, digits and a few symbols, so lower-case letters and characters such as ? and = push the code into byte mode. Writing the link in capitals is safe for the scheme and the domain, which the URI standard treats as case-insensitive. The path is case-sensitive by default, so your site has to treat /Q/2026-017 and /q/2026-017 as the same address.
Every test code from 15 to 40 mm (0.6 to 1.6 in) decoded correctly in software after we rasterised it. That shows the codes are valid at those sizes. It does not show how they behave once burned into wood: grain, char, engraving depth and finish all affect contrast. We have not yet run physical engraving tests on oak, walnut or ash, and we will update this guide when we do.
Practical advice for engraving
- Aim for about 25 mm (1 in) across. That leaves margin above the minimum sizes we calculated.
- Test on an offcut of the same species with the same finish. Scan it with more than one phone before engraving the piece.
- Watch contrast on dark timbers. On walnut and other dark woods, a plain engraving may not stand out enough; filling the engraving with a contrasting filler can help.
- Keep the quiet zone clear. Grain figure is usually fine, but other engraving, edges or fixings inside the margin can stop a scan.
- Put a short URL and the serial next to the code. If the code becomes unreadable, someone can still type the address or quote the number.
- Use a URL you will keep. The code will outlive several versions of your website, so choose a short, stable path on a domain you control.
The page the code opens is a good place for materials, care notes and the piece's history. Our care card tool can produce the care text to go with it.
Sources
- QR Code Laser Engraving: A Complete Guide, OMTech: guideline that each module should be at least 0.5 mm wide, and the need for a quiet zone
- Point for determining the code area, DENSO WAVE: four-module margin on all sides; symbol size equals modules multiplied by module size
- Information capacity and versions of QR Code, DENSO WAVE: version 1 is 21 × 21 modules, with four more per side for each version
- Alphanumeric mode encoding, Thonky QR code tutorial: alphanumeric mode encodes upper-case letters only
- RFC 3986: Uniform Resource Identifier generic syntax, IETF: scheme and host are case-insensitive; other components are case-sensitive unless the scheme says otherwise
- On-metal NFC stickers, GoToTags: metal affects NFC tags, and on-metal tags are made for that case
Questions this guide gets asked
Should the serial number include the client's name?
No. Furniture changes hands, and a name on the piece or in a public record ties a future owner to someone they have never met. Keep the client's details in your own records against the serial number instead.
Can I change a serial number after it has been issued?
Treat issued numbers as permanent. If a number was given to a piece that was never delivered, retire it and note why, so the sequence still makes sense later. Reusing numbers breaks the link between the mark and its records.
What happens to the QR code if I change my website?
The code keeps pointing at whatever address it encodes, so that address needs to keep working for the life of the piece. Use a short path on a domain you control, and set up redirects if you ever move the pages behind it.
Will a QR code survive the piece being refinished?
Sanding removes surface marks, and a shallow engraving on a show surface may not survive a full refinish. Engrave on an underside or inside face that is unlikely to be sanded, and keep the human-readable serial nearby as a fallback.
Do I need an error correction level setting?
Most QR generators default to a sensible level. Higher error correction tolerates more damage but needs more modules for the same data, which makes the code larger at a given module size, so test what your generator produces before engraving.