UPC-A Barcode Generator

How to use UPC-A Barcode Generator

1. 1

   Type the 11 digits of your UPC (number system, manufacturer and product code) — the 12th check digit is added automatically. Paste all 12 and it is verified instead.

2. 2

   Optionally add a UPC-2 or UPC-5 supplemental code, and set the bar height and width for your label.

3. 3

   Check the preview and the encoded number shown under it against your product listing.

4. 4

   Download SVG for packaging artwork or PNG for documents and listings — or switch to Batch for a whole catalogue as a ZIP.

What a UPC-A barcode generator does with your twelve digits

A UPC-A is twelve digits: a one-digit number system, the manufacturer prefix GS1 assigned to your company, your own product code, and a check digit at the end that is computed from the first eleven. Scanners recompute that digit every time and refuse the code if it does not match — which is why a barcode typed by hand from a spreadsheet so often works on screen and fails at the register. Here you type the eleven digits you control and the twelfth is calculated and shown under the preview; paste all twelve and it is verified, with the correct digit spelled out if yours is wrong.

The layout follows the retail standard: guard bars left, centre and right, the number system digit and check digit printed outside the bars, the two groups of five underneath. Bar height and width are adjustable — keep the width at two to three pixels per module for label printers — along with the quiet zone, text and colours. Retail codes should stay dark on light: laser scanners at tills cannot see red bars at all.

UPC-A for Amazon, retail listings and packaging

The most common reason to generate a UPC today is a marketplace listing. Amazon, Walmart, eBay and the rest ask for a UPC on most product categories and check the number against the GS1 database — so the image can come from here, but the number must be one GS1 licensed to you or to the brand you are reselling. A made-up twelve-digit number will scan perfectly and still be rejected at listing time.

For physical packaging, download SVG: it is vector, so the module widths survive being placed in a design file and scaled by a printer. PNG at 3× or 4× is the right choice for listing images, spec sheets and thermal label printers that only take bitmaps. If a magazine or a coupon needs a supplemental code, add a two- or five-digit add-on and it is drawn beside the main code with the standard gap.

• Type 11 digits → check digit added and shown; type 12 → verified
• Optional 2- or 5-digit supplemental code
• SVG for packaging, PNG up to 4× for listings and label printers
• Same number reads as EAN-13 in Europe with a leading 0

Bulk UPC barcodes for a catalogue, without uploading it

Every step runs inside your browser, using the WebAssembly and Canvas APIs your device already ships with. No file is uploaded, no copy is kept, and nothing sits in a queue on a server waiting to be deleted — which is also why the tool keeps working with the network disconnected.

That matters for UPCs more than most content, because a product list with its codes is a supplier's inventory in plain text. Switch to Batch, paste one UPC per line from your spreadsheet — eleven or twelve digits, up to 500 — and download a ZIP with a PNG per product plus a CSV manifest pairing each file with its number. Invalid entries are listed and skipped rather than silently turned into labels no scanner will read. Print one label and test it with a phone before running the whole set: a perfect check digit does not survive being printed too small or with the quiet zone cropped.

Frequently Asked Questions

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