Barcode generator

Pick a symbology, type a value, and you get the barcode — as a PNG or an SVG, with the check digit worked out and printed under the bars. Ask for a run of consecutive codes and it comes back as a sheet of captioned labels to print and stick. It also checks a code you already have. Free, no account, nothing stored.

What it does, and why it is here

Almost every retail barcode ends in a digit that is not data: it is a check digit, computed from the ones before it, and a scanner rejects any code whose last digit does not agree with the rest. That is the part that goes wrong. A product number copied from a supplier sheet is twelve digits, the symbology wants thirteen, and the thirteenth is not a zero — it is arithmetic.

So the tool takes the value with or without its check digit and tells you which case it was in: computed and added, or verified against what you gave. Paste a whole code in verify mode and it says plainly whether the digit agrees, and what it should have been if not.

The second thing it does is the part people actually need on a Tuesday: a run of codes on a printable sheet. Numbering a hundred assets, labelling a shelf, marking a season’s stock — that is one sequence, one caption per label, one PDF, laid out to be cut or peeled.

What you fill in

• Mode — one code, a run of consecutive codes for a sheet, or the verdict on a code you paste.
• Symbology — eight of them, from EAN-13 to PDF417. The table below says which to pick.
• Value to encode — for EAN, UPC and ITF-14, with or without the check digit; spaces and dashes are ignored, so a value copied from a catalogue works as it is.
• Codes in the sequence — up to 100, the start value included. Each gets its own check digit and its own label.
• Copies — how many times each code repeats on the sheet.
• Label caption — printed above the code on the PDF sheet and there only: the product’s name, its price, whatever a shelf is read by without scanning.
• Width in pixels.

What you get back

• The barcode, as a PNG and as an SVG. Use the SVG for anything going to a printer: a linear code is bars and gaps, and vector bars stay exactly the widths a scanner expects.
• The check digit verdict — added, verified, wrong (with the digit the arithmetic calls for), or a plain statement that this symbology carries none.
• What this code is — the part no other free generator bothers with. For a GS1 number it names the prefix and the member organisation that allocated it; it recognises an ISBN-13 and gives the ISBN-10 beside it, recognises an ISSN, shows a UPC-A as its EAN-13 equivalent and back, and reads the GTIN-13 inside an ITF-14 along with its packaging indicator.
• A sheet to print, with your caption above each label. Printing that page prints the labels alone, without the rest of the site — set the printer to actual size, or the bars come out too narrow to scan.
• A way on to the QR generator, to encode the same value as a QR code.

What it does not do

It does not allocate numbers. A barcode is a drawing of a number, and a number that identifies a product in trade has to be bought from GS1 — a code you invent will scan perfectly and collide with somebody else’s product on a real till. For internal use, where nothing leaves your building, invent freely.

No logos and no colours: both risk the read, and neither is worth it on a code whose only job is to scan.

And it does not look anything up. It tells you what a number says about itself — its prefix, its structure, its check digit — not what product it belongs to.

Which symbology, and when

If you do not know: Code 128 for anything internal, EAN-13 if you are putting a product on a shelf and hold a GS1 prefix. Those two cover most of it.

Questions

Is it free? Can I use the images commercially?

Yes to both. No account, no watermark, no limit.

Do you keep what I encode?

No. The value is used to draw the code and then forgotten — not stored, not logged, not indexed.

Why was my value refused?

Either the length is wrong for the symbology — EAN-13 wants twelve digits plus the check, UPC-A eleven — or it contains characters that symbology cannot carry. Code 39 takes digits, capitals and a few symbols; Code 128 takes anything.

Can I get a vector file?

Yes — download the SVG. It is the right format for print, and any design or label program will open it.

Do you draw DataMatrix and PDF417?

Yes, both, alongside the six linear symbologies. DataMatrix is the denser choice on a small label; PDF417 carries far more text.

My scanner reads it on screen but not on paper.

Almost always the print scale or the quiet zone. Reprint at actual size — not “fit to page” — and leave the white margin around the code intact.

Where does the prefix information come from?

The public GS1 prefix table. It names the member organisation that allocated the company number — not where the product was made, which is a persistent myth about the first three digits.

Can I number a hundred assets in one go?

Yes: choose the sequence mode, give the starting value and how many, add a caption, and print the sheet. Each code in the run gets its own check digit.

Sources and further reading

• GS1 barcode standards — the body that allocates retail numbers and defines the symbologies.
• EAN-13 — structure and the check-digit arithmetic.
• GTIN — the number behind EAN, UPC and ITF-14.