Where do I get a UPC number?

From GS1 US (or the GS1 office in your country). They license a company prefix; you assign item numbers under it. This site does not sell numbers.

My UPC has 12 digits. Do I type all of them?

Either works. With 12 digits the generator checks that the last one is the correct check digit and tells you if it is not.

Can I make a UPC smaller than 80%?

Not within the GS1 specification. Small packs use UPC-E, which is about half as wide, if the number can be shortened.

Does Amazon accept these barcodes?

Amazon checks that the UPC belongs to the brand in the GS1 database. The barcode image is fine; the number must be one GS1 licensed to you.

UPC barcode generator

Type the first 11 digits of your UPC and the 12th, the check digit, is calculated for you. The code is drawn at the GS1 nominal size (0.33 mm module, 100%) unless you change it.

Size with quiet zones37.3 × 27.4 mm1.47 × 1.08 in

Fits a 63.5 × 33.9 mm label (A4, 24 per sheet) or 4 × 2 in (Letter, 10 per sheet).

Encoded: 036000291452

Check digit 2 added (GS1 modulo-10).

37.3 × 27.4 mm

How to use it

Type the 11 digits of your UPC (the number GS1 issued to your product). If you type all 12, the check digit is verified.
Keep the size at 100% (0.33 mm module) or choose between 80% and 200%. Smaller than 80% is out of the UPC specification.
Keep the digits under the code: retail scanners do not need them, but cashiers type them when a code does not scan.
Download SVG or PDF for packaging artwork, or PNG at your printer's resolution. Print at 100% (actual size). “Fit to page” shrinks the code and can push the module width below what scanners accept.

UPC-A sizes

UPC-A has 95 modules of bars plus a quiet zone of at least 9 modules on each side, so the full width is 113 modules. The bar height scales with the module width.

UPC-A at common magnifications (GS1 nominal height)
Magnification	Module	Width with quiet zones	Bar height
80%	0.264 mm	29.83 mm (1.17 in)	18.28 mm
100%	0.330 mm	37.29 mm (1.47 in)	22.85 mm
150%	0.495 mm	55.94 mm (2.20 in)	34.28 mm
200%	0.660 mm	74.58 mm (2.94 in)	45.70 mm

What the 12 digits mean

The first digit is the number system (0, 1, 6, 7, 8 for most products; 2 for variable-weight items packed in store; 3 for drugs; 5 for coupons). The next digits are your GS1 company prefix and the item reference you assign. The last digit is the check digit.

A UPC-A number is a GTIN-12. Outside North America it is read as the EAN-13 with a leading zero, so the same barcode works worldwide.

How the check digit is calculated

Multiply the digits in odd positions (1st, 3rd, … 11th) by 3, add the digits in even positions, and take the number that brings the total up to the next multiple of 10. For 03600029145: 3 × (0+6+0+2+1+5) + (3+0+0+9+4) = 42 + 16 = 58, so the check digit is 2 and the UPC is 036000291452.

Questions

Where do I get a UPC number?: From GS1 US (or the GS1 office in your country). They license a company prefix; you assign item numbers under it. This site does not sell numbers.
My UPC has 12 digits. Do I type all of them?: Either works. With 12 digits the generator checks that the last one is the correct check digit and tells you if it is not.
Can I make a UPC smaller than 80%?: Not within the GS1 specification. Small packs use UPC-E, which is about half as wide, if the number can be shortened.
Does Amazon accept these barcodes?: Amazon checks that the UPC belongs to the brand in the GS1 database. The barcode image is fine; the number must be one GS1 licensed to you.