Tools
QR code lab label generator
Every QR code here is computed on your device and drawn as vector modules. No image service, no upload, no request carrying your sample identifiers.
Why the payload should be short
A QR code's module count grows with its payload. More modules in the same physical square means smaller modules, and below roughly 0.4 mm per module a phone camera struggles — especially through a freezer's frost or a scratched vial.
A short identifier that your own inventory resolves is therefore worth much more than a self-describing URL. “S-2026-0412” is 11 bytes; the same information as a tracked URL is often 80 or more, and the difference shows up as a code you have to hold the phone still for.
Module size against label size
| Payload | Version | Modules | 10 mm code | 12 mm code | 15 mm code |
|---|---|---|---|---|---|
| ≤ 14 bytes | 1 | 21 + quiet | 0.34 mm | 0.41 mm | 0.52 mm |
| ≤ 26 bytes | 2 | 25 + quiet | 0.29 mm | 0.35 mm | 0.44 mm |
| ≤ 42 bytes | 3 | 29 + quiet | 0.25 mm | 0.30 mm | 0.38 mm |
| ≤ 62 bytes | 4 | 33 + quiet | 0.22 mm | 0.27 mm | 0.33 mm |
What the generator does differently
- Drawn as vectors, not pixels
- Modules are rectangles in the PDF, so there is no resampling and no grey edge. A raster QR scaled to a physical size almost always lands between dot boundaries.
- Byte-exact payloads
- The payload is encoded as given, including non-ASCII, and the byte count is shown against the 512-byte practical limit before you print.
- Nothing leaves the device
- The encoder runs in your browser. Sample identifiers are frequently patient- or project-linked; sending them to an image service to get a picture back is not a reasonable trade.
- Quiet zone preserved
- The code keeps its margin even when the block is resized, because a QR without a quiet zone fails on exactly the scanners you cannot test.
Common questions
- Are the QR codes uploaded anywhere?
- No. They are computed in your browser and drawn into the label locally. The page makes no request carrying label content.
- How small can a QR code on a lab label be?
- As a rule of thumb keep modules at or above 0.4 mm. With a short identifier that means roughly a 10–12 mm code; with a long URL you will need 15 mm or more for the same reliability.
- What should the QR code contain?
- The shortest thing that is unique inside your own system. Resolve it to detail in your inventory rather than encoding the detail on the vial.
Open it in the editor
The editor loads at 38.1 × 19.05 mm with a worked example in place. It runs entirely in your browser: nothing you type is uploaded, and there is no account to make.
Last reviewed 2026-08-24.