UPC & EAN check digit calculator
Paste a barcode: it tells you whether the last digit checks out, completes it if it is missing, and spots the leading zero your spreadsheet ate.
- Free
- No sign-up
- Runs in your browser
The digits you type — nothing else. No catalogue lookup, no ASIN match: the arithmetic runs in your browser and nothing is sent anywhere.
8, 12, 13 or 14 digits (EAN-8, UPC-A, EAN-13, ITF-14). Spaces and hyphens are ignored. Paste it without the check digit and it gets calculated for you.
Type or paste a barcode and the answer appears here.
How it is calculated
check digit = (10 − (Σ digit × weight) mod 10) mod 10
- digit
- each digit of the code except the last one (the check digit itself), read right to left
- weight
- 3 for the digit next to the check digit, then 1, then 3, then 1 — alternating leftwards
- mod 10
- the remainder after dividing by 10. The outer one is not decoration: without it a sum that is already a multiple of 10 would give a check digit of 10, which is not a digit
Worked example
- Take UPC-A 036000291452. Drop the last digit: the payload is 03600029145.
- Right to left: 5×3 + 4×1 + 1×3 + 9×1 + 2×3 + 0×1 + 0×3 + 0×1 + 6×3 + 3×1 + 0×3.
- That is 15 + 4 + 3 + 9 + 6 + 0 + 0 + 0 + 18 + 3 + 0 = 58.
- 58 mod 10 = 8, so the check digit is (10 − 8) mod 10 = 2 — which is the last digit printed on the package. The code is valid.
One barcode is arithmetic. A supplier list is the actual job.
This page fixes a digit. It cannot tell you whether your account may sell that item, what Amazon charges for it, or whether anyone buys it. FlipIQ Batch takes the whole price list — Excel, CSV or a 300-page PDF — and returns the rows worth buying.
Analyse a supplier list freeMore free tools: Amazon FBA & FBM revenue calculator · The seven Amazon restriction types. Read alongside them: Amazon wholesale suppliers, and how to read their price list · What the numbers on a supplier row mean. Or see the three places to ask the engine and the rest of the free tools.