Make a scannable barcode for stock, assets or retail. Code 128 for anything internal, or EAN and UPC for products that go on a shelf — with the check digit worked out for you.
Code
Appearance
The quiet zone is the empty margin either side of the bars. Scanners need it — a barcode printed hard against a box edge or another graphic often will not read at all.
Use the SVG for anything that will be printed — it stays razor-sharp at any size, and crisp edges are what a scanner actually reads. The PNG is fine for a screen or a quick label.
Choosing the right barcode for the job
There are two different situations here. If you are labelling your own stock, assets or shelves and only your own systems will read the codes, Code 128 is the right answer: it takes letters, digits and punctuation, so your existing reference numbers can go straight onto the label unchanged.
If the product is going to be scanned at somebody else’s till, you need a retail symbology — EAN-13 in most of the world, UPC-A in North America, EAN-8 where the packaging is too small for a full code. These are not free-form: the numbers are allocated to you, and the final digit is a check digit calculated from the others. Enter your number without it and it is worked out for you; enter it with one and it is verified, so a transposed digit is caught before it reaches a printer.
Common questions
Which barcode type should I use?
Code 128 for internal stock numbers, asset tags and shelf labels. EAN-13 for retail products sold internationally. UPC-A for retail in the United States and Canada. EAN-8 for small packaging where a full-length code will not fit.
What is a check digit?
The last digit of a retail barcode, calculated from all the digits before it. Scanners use it to detect a misread. You do not have to work it out — enter the number without it and it is added automatically.
Can I make up my own EAN-13 number?
You can generate a valid-looking one, but you should not use it on a product for sale. Retail numbers are allocated through GS1 so they are globally unique; an invented number may already belong to something else and will cause problems at the till. For internal use where nothing leaves your own premises, Code 128 avoids the question entirely.
Why does my numeric code look shorter than expected?
Code 128 packs two digits into each symbol when the content is all digits and of even length, which makes the barcode roughly half as wide for the same information. It scans identically.
How big should a barcode be printed?
Keep the quiet zone — the blank margin either side — and avoid shrinking the code much below about three centimetres wide for Code 128. A barcode printed hard against a box edge or another graphic very often will not read at all.
These utilities are the small end of what we do. TechnoSyn builds custom applications, business systems and internal tools for people who depend on them daily. If you have something larger that needs building, tell us what you are trying to do.