UPC-A Barcode Generator

What a UPC-A barcode is

UPC-A is the 12-digit barcode on almost every product sold in the USA and Canada. The number it carries is a GTIN-12, issued through GS1 US or GS1 Canada, and the bars let a checkout scanner read it in any direction in a fraction of a second.

It is older than most people expect. George Laurer designed the symbol at IBM in 1973, and the first product scanned with it was a 10-pack of Wrigley's Juicy Fruit gum at Marsh Supermarket in Troy, Ohio, on 26 June 1974. Europe adopted a 13-digit version, EAN-13, a few years later. A UPC-A is in fact an EAN-13 whose first digit is 0, and since 1 January 2005 North American tills have had to read both.

The UPC is not going away. Under GS1 US Sunrise 2027, US tills are also being made ready for 2D barcodes, so a QR code carrying a GS1 Digital Link can sit next to the UPC on the same pack.

The number comes before the barcode

The barcode is free; the number is not. In the USA it comes from GS1 US, in Canada from GS1 Canada. These are the GS1 US prices, read on 9 October 2026:

Each size, colour and flavour gets its own number. Numbers sold cheaply by resellers were licensed to other companies, and Amazon checks the GS1 database and removes listings whose UPCs do not match. Once you have your number, type its first 11 digits into the generator above. Not sure whether a number in an old spreadsheet is a UPC, an EAN or an ISBN? The barcode identifier tells you from the digits.

For a whole range, paste the list in bulk mode. Numbers with 12 digits come out as UPC-A and numbers with 13 digits as EAN-13, so a mixed export from a shop system works as it is.

What each part of a UPC means

The first digit used to be called the number system. Today it is the start of the company prefix GS1 US gave the brand, and most products start with 0, 1, 6, 7, 8 or 9. Two first digits still mean something special: 2 is for weighed items priced in the store, such as deli meat, and 4 is for numbers a company uses only internally. Drug makers number their packs from their FDA labeler code, and those numbers often start with 3. The 5 that once marked coupons is reserved by GS1 US for future use.

Next comes the rest of the company prefix, then the item reference the company assigns to each product. Prefixes vary in length, so the split between the two moves from brand to brand. The 12th digit is a check digit, calculated from the other eleven so a scanner can tell a misread from a real code. Type the first 11 digits and the generator adds it. To check a whole list of UPCs before you print, use the check digit calculator.

Where the bars come from

Each digit is drawn as two bars and two spaces across 7 modules, the narrowest unit of width. Guard bars, slightly longer than the rest, frame the code at the start, centre and end. The left six digits are drawn with an odd number of dark modules and the right six with an even number, which is how a scanner knows whether it read the code from left to right or backwards.

The standard behind it

The symbol is defined in ISO/IEC 15420, and the rules for size, placement and numbering are in the GS1 General Specifications. Every UPC-A is 95 modules wide between its quiet zones, whatever the number.

The right size for a UPC

GS1 sets the size by the width of the narrowest bar, the X-dimension; printers call the scale magnification. At 100% that bar is 0.330 mm (13 mils), the barcode measures 37.29 mm (1.47 in) across including its quiet zones, and the bars are 22.85 mm tall. You can go from 80% to 200%. Below 80% the generator shows a warning that says what GS1 allows. If your packaging spec gives sizes in mils or inches, switch Units in Settings.

These figures come from GS1's magnification table. Bar height does not include the digits.

The digits add about 3 mm below the bars. That explains the figure 1.469 by 1.020 in (37.29 by 25.91 mm) in older US guides: it is the 100% size with the digits included.

The quiet zone is 9 modules of blank space on each side, about 3 mm at 100%. The first and last digits print inside it, small, but nothing else should. Keep the full bar height too. GS1 allows shorter bars only when nothing else works, such as on a tightly curved surface, because short bars are hard to read at an angle. If the barcode is too wide for a narrow box side, Rotation in Settings turns it 90 degrees so it runs up the side instead.

Printing a UPC on a label printer

Many sellers print UPC stickers on a 203 dpi thermal label printer. Its dots are 0.125 mm wide, so it cannot print a 0.330 mm bar: it prints 2 dots (0.250 mm) or 3 dots (0.375 mm), and a bar in between comes out uneven. Choose Label printer under Printing on, then 203 dpi, and the generator snaps the bars to whole dots. A 100% UPC becomes one at about 114%, 42.4 mm wide.

Pick your printer's resolution to see which UPC sizes it prints sharp.

Download the PNG and print it at 100% with scaling turned off. If Amazon or a buyer reports that the code cannot be scanned, print the test page from the download area first and measure its 100 mm ruler. If the ruler is not 100 mm long, the printer driver is scaling the page, and every barcode on that roll is the wrong size.

UPC-A or EAN-13?

If you sell only in the USA and Canada, UPC-A is what buyers and retailers expect to see. If you also sell in Europe or elsewhere, either works: every modern scanner reads both, and the number is the same GTIN with or without the leading zero. Many brands print UPC-A for North America and keep the EAN-13 form in their product data.

Very small packs once used UPC-E, a short form for numbers with enough zeros. GS1 US no longer licenses new UPC-E prefixes, so for a new product scale the UPC-A down to 80%, or ask GS1 US about an EAN-8.

US magazines and some books carry a small second barcode to the right of the main one: an EAN-2 or EAN-5 add-on. Add-on in Settings draws either next to a UPC-A.

Mistakes that make a UPC fail

The most expensive one is the number itself. A UPC bought cheaply from a reseller was licensed to another company years ago, and GS1 still lists that company as the owner. Amazon and many large retailers check, and they reject it.

The rest are print problems. A wrong check digit, usually from typing the number by hand, produces a barcode that will not scan at all; the generator stops you before you download it. If a digit on an old label is unreadable, the barcode repair tool can work it out from the others. A barcode printed below 80%, or with a box edge running through its quiet zone, may scan at your desk and fail on a busy checkout. And a 300 dpi PNG stretched to twice its size in a design program blurs the bars; send EPS, PDF or SVG to whoever lays out the packaging.

Colour is the other trap. Scanners read with red light, so red, orange and yellow bars disappear. If the design calls for coloured bars, set the colours in Settings: the generator measures the contrast a scanner would see and warns you below 75%. Keep the 12 digits under the bars as well. Own text can replace them on internal labels, but checkout staff key in the digits when a scan fails.

Frequently asked questions