UPC Check Digit Calculator
A UPC-A has 12 digits, and the last one is calculated from the other 11. Enter your 11 digits to find it and see the finished barcode.
How it works
- 1Type the first 11 digits of the UPC.
- 2Read the check digit and the full 12-digit number.
- 3Download the barcode as a PNG or SVG.
The UPC check digit formula
Weights alternate 3 and 1, starting with 3 on the first digit from the left for an 11-digit UPC. Sum the weighted digits, take the remainder when dividing by 10, and subtract it from 10 (using 0 if the remainder is 0).
Common mistakes
Leaving out a leading zero is the classic error: UPCs often begin with 0, and spreadsheets silently delete it. Format the column as text so every number keeps its 12 digits.