UPC generator

What a scanner needs from a UPC

A checkout scanner measures the widths of bars and gaps, so a UPC only works if those widths survive printing. Barcode sizes are given by the narrow bar, also called a module, sometimes in mil, which is a thousandth of an inch. GS1 sets it at 0.33 mm, and allows 0.264 mm to 0.66 mm for retail checkout. That is the 80 to 200 percent range people mean when they talk about barcode size.

The scanner also needs empty space on both sides. A UPC-A wants 9 modules of clear space left and right, which is 2.97 mm at the target size. Artwork or a crop inside that space can stop a scan, so the hatched areas in the preview show exactly what to leave alone.

Make a UPC barcode in three steps

1. Type 11 digits, or all 12 if you have the full number. The preview redraws as you type.
2. Choose a size. Keep 100 percent unless your pack is too small or your printer needs bigger bars. Bar height follows the size until you change it.
3. Download SVG or PDF for a designer or a page layout, or PNG for a label printer. Print the test sheet and check that the 50 mm ruler measures 50 mm on paper.

UPC sizes GS1 allows

Width here includes the clear space. A shorter barcode is possible if your pack truly has no room. GS1 warns that cutting bar height removes the ability to scan from any angle.

Five UPC sizes from 80 to 200 percent, with bar height and width

Size	Narrow bar	In mil	Bar height	Full width
80%	0.264 mm	10.4	0.72 in (18.28 mm)	1.17 in (29.83 mm)
100%	0.33 mm	13	0.9 in (22.85 mm)	1.47 in (37.29 mm)
120%	0.396 mm	15.6	1.08 in (27.42 mm)	1.76 in (44.75 mm)
150%	0.495 mm	19.5	1.35 in (34.28 mm)	2.2 in (55.93 mm)
200%	0.66 mm	26	1.8 in (45.7 mm)	2.94 in (74.58 mm)

Why bars are rounded to whole printer dots

A printer cannot print part of a dot. A 0.33 mm bar on a 203 dpi thermal printer works out to 2.64 dots. If the file leaves that to the printer, some bars come out 2 dots wide and others 3. The bar widths are the data, so that unevenness is what makes a barcode hard to read.

The PNG download avoids it by drawing every bar to a whole number of dots at the resolution you pick. At 203 dpi the narrow bar becomes 3 dots, which prints at 0.375 mm, or 114 percent. At 300 dpi it becomes 4 dots, or 0.339 mm. The rounding never carries a size outside the GS1 range, and the PNG readout tells you what will actually come out of the printer. The file also records its resolution, so a page layout program places it at its true size.

What the opening digits say

GS1 gives each range of numbers a job. Reading a UPC, add an unseen zero to the front first, so a number starting with 4 falls in GS1's 04x range.

What the opening digits of a UPC say

UPC starts with	GS1 range	What it is for
0, 1, 3, 6, 7, 8, 9	001 to 019, 030 to 039, 060 to 099	Numbers licensed through GS1 US
2	020 to 029	Local schemes, such as store-packed food sold by weight
4	040 to 049	Use inside one company
5	050 to 059	Held back by GS1 US

For stock you run yourself, use a number starting with 4, because it cannot match someone else's product. Do not copy a number from another company's packaging, and do not print a made-up number and present it as a real product code. The full EAN-13 prefix reader covers numbers from outside North America.

The check digit, worked through

Take 03600029145, the number GS1 uses in its own check digit example. Starting from the right-hand digit, multiply alternately by 3 and 1, and add the results: 0 x 3 + 3 x 1 + 6 x 3 + 0 x 1 + 0 x 3 + 0 x 1 + 2 x 3 + 9 x 1 + 1 x 3 + 4 x 1 + 5 x 3 = 58. The next multiple of ten is 60, and 60 minus 58 is 2, so the full number is 036000291452.

The sum for your own number updates as you type. For numbers you only want to test, the check digit calculator handles EAN, GTIN-14, SSCC and ISBN too.

UPC-A or UPC-E

UPC-E is a shorter barcode for packs too small for UPC-A. It leaves out zeros in set positions, so only numbers with those zeros can use it. The number 012345000065 squeezes down to 01234565, and a scanner rebuilds the full 12 digits from it. Most numbers do not fit, and the tool says so when yours does not.

Other barcodes for the same product

A case of your product needs its own number and a sturdier symbol, which the ITF-14 carton barcode generator builds from your UPC. For bins and shelves, a Code 128 label holds letters as well as digits. If you are still deciding whether you need a licensed number, how to get a UPC code sets out the route and the costs. The number itself is explained in what a UPC code is.

Reading the number on a package

If you are copying a number from an existing product, where the UPC code is on a product shows which digits to type and which to leave out. The number itself is a GTIN-12. What a GTIN is explains how it relates to the EAN on an imported product and to the code on its shipping case. A phone camera is enough to scan a test print before you commit to a run.