UPC Barcode & Check Digit Calculator
Check the UPC you bought from GS1, or find its last digit — and get its barcode.
Your results will appear here
Type your 12-digit UPC to check it and see its barcode.
How the check digit works
The last digit of a UPC is a check digit: it is worked out from the other 11, so a scanner can tell when a number was typed or printed wrong. Starting from the right, multiply the digits by 3, 1, 3, 1 and so on, add them up, and take what is needed to reach the next multiple of 10.
This page checks a full number you have, or works out the last digit of one you are setting up. It also draws the UPC-A barcode, with the numbers printed under the bars, ready for your label.
A worked example
GS1’s sample number starts 01234567890. From the right, 0×3 + 9×1 + 8×3 + 7×1 + 6×3 + 5×1 + 4×3 + 3×1 + 2×3 + 1×1 + 0×3 = 85. The next multiple of 10 is 90, so the check digit is 5, and the full UPC is 012345678905.
Common mistakes
- Buying cheap UPCs from a reseller. Stores and marketplaces can look up who a number is registered to, so a resold one can be refused. Get yours from GS1 US, or your country’s GS1.
- Using one UPC for several scents or sizes. Each product version needs its own.
- Printing the barcode too small or stretched. Keep it at its full proportions, with white space on both sides.
- Typing the number by hand without checking it. One wrong digit makes the barcode unreadable at the till.
These numbers are starting points. Always burn test the finished candle before you sell it.
Common questions
What is a UPC check digit?
The last digit of a UPC, calculated from the other 11 with GS1’s mod-10 rule. It lets a scanner catch a wrong number before it rings anything up.
Where do I get a UPC for my candles?
From GS1 US in the United States, or your country’s GS1 member organization elsewhere. The number is then registered to your business.
Does CandleEasy make UPC numbers?
No. A UPC has to come from GS1. This page only checks a number you already have and draws its barcode.
What is the difference between UPC-A and EAN-13?
UPC-A has 12 digits and is used in the United States and Canada. EAN-13 has 13 and is used in most other countries; a UPC-A with a 0 in front is a valid EAN-13. This page checks both, and draws UPC-A barcodes.
Do I need a UPC to sell wholesale?
Many shops ask for one, because their checkout rings products up by UPC. Ask each buyer what they need, and see our SKU & Barcode Generator for your own codes.
Ready to go beyond the numbers?
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