Quick answer: type digits and dashes, keep “Add check digit” on (one check digit C, plus K when the data is 10 characters or longer) and download the barcode.
About Code 11
Intermec developed Code 11 in 1977 for telecommunications equipment, where component and circuit numbers consist of digits and dashes. Each character uses three bars and two spaces, which makes the code fairly dense, but it has weak self-checking – one printing defect can turn one digit into another. That is why the check digits matter.
| Characters | 0–9 and - |
| Check digits | C (modulo 11, weights 1–10); K added for 10 characters or more |
| Also known as | USD-8 |
How to make a Code 11 barcode
- Enter digits and dashes. For example a circuit or equipment number such as 123-4552.
- Keep the check digits. Code 11 has little built-in protection, so the C (and K) check digits are recommended.
- Download. PNG for labels, PDF or SVG for artwork.
- Test on your scanner. Phone apps and our scan test do not read Code 11 – confirm with your handheld.
Should you use Code 11 for something new?
Only to match an existing system. For new labels with digits and dashes, Code 128 is better supported and more robust.
Reading Code 11 reliably
Code 11 is a discrete code: every character stands on its own and is separated from the next by a narrow gap. Each character has five elements – three bars and two spaces – and one or two of them are wide. Because a single smudged bar can turn one valid character into another, Code 11 was always meant to be used with its check digits switched on in both the printer and the scanner. If your handheld shows an extra digit or two at the end of every scan, it is transmitting the check digits; most scanners have a setting to strip them.
Sizes that work
- Bar width 0.25–0.33 mm for small equipment tags printed on thermal transfer labels.
- A height of at least 8–10 mm, or 15 % of the barcode length, so a handheld does not have to be aimed precisely.
- A quiet zone of 10 bar widths on both sides – the start and stop characters are easy to miss if text is printed too close.
For labels that will be scanned by many different devices, consider moving to Code 128: it carries the same digits and dashes, needs no separate check-digit settings and is enabled on every scanner by default.
Frequently asked questions
Why are there two check digits on my long barcode?
Code 11 adds a second check digit (K) when the data has 10 or more characters, to keep misreads unlikely.
Can I switch the check digits off?
Yes, but only do it if your scanners are set to read Code 11 without check digits.
Can Code 11 encode letters?
No, only digits and the dash.
What does a Code 11 label usually contain?
Circuit, port or equipment numbers made of digits separated by dashes, as used in telephone exchanges and network cabinets.
Is the dash encoded or only printed?
It is encoded. The dash is one of the 11 characters that give Code 11 its name.