Free tool · No sign-up
GS1 check digit calculator.
Enter an EAN, UPC, GTIN, GLN or SSCC without its last digit — the calculator adds the check digit using the GS1 algorithm and shows the calculation digit by digit.
7 digits (EAN-8), 11 (UPC-A), 12 (EAN-13 / GTIN-13 / GLN), 13 (GTIN-14), 16 (GSIN) or 17 (SSCC).
Examples:
To check complete numbers and GS1 element strings, use Check a barcode.
01 Formats
Which numbers it handles
The format follows from the number of digits you enter.
| Format | Input | With check digit | Used for |
|---|---|---|---|
| EAN-8 (GTIN-8) | 7 | 8 | Small packages |
| UPC-A (GTIN-12) | 11 | 12 | North American retail |
| EAN-13 (GTIN-13) | 12 | 13 | Retail item number |
| GLN | 12 | 13 | Location and party number |
| GTIN-14 / ITF-14 | 13 | 14 | Outer case, trade unit |
| GSIN | 16 | 17 | Shipment number |
| SSCC | 17 | 18 | Pallet, logistic unit |
02 Algorithm
How the check digit is calculated
- Multiply the digits alternately by 3 and 1, from right to left.
- Add up all products.
- Subtract the sum from the next multiple of ten — the result is the check digit.
EXAMPLE · EAN-13
400638133393?
4·1 + 0·3 + 0·1 + 6·3 + 3·1 + 8·3 + 1·1 + 3·3 + 3·1 + 3·3 + 9·1 + 3·389
Next multiple of ten90
Check digit90 − 89 = 1
In the warehouse, not at the desk
Check digits verified on every scan
The barValid app verifies the check digit of every GTIN and SSCC the moment you scan the code — together with expiry date, batch and every other application identifier.
FAQ
Frequently asked questions
How is the GS1 check digit calculated?
Working from right to left, multiply the digits alternately by 3 and 1, starting with 3 for the digit right before the check digit. Add up the products. The check digit is the difference between that sum and the next multiple of ten; if the sum is already a multiple of ten, the check digit is 0.
Is the calculation the same for EAN, UPC, GTIN, GLN and SSCC?
Yes. Every GS1 key with a check digit uses the same modulo-10 algorithm with weights 3 and 1. Only the length differs, and the weighting always starts on the right.
I have 13 digits — is that an EAN-13 or a GTIN-14 without its check digit?
Only whoever has the number can tell. That is why the calculator shows both: the check digit a GTIN-14 would get, and whether the last digit is already correct when read as an EAN-13.
Does the check digit give me a valid barcode number for my product?
No. The check digit only makes a number formally correct. A GTIN that retailers accept needs a GS1 company prefix, which you get from your national GS1 organisation.
What is the difference to checking a number?
Here you enter the number without its check digit and get it calculated. If you have a complete number or a full GS1 element string such as (01)…(17)…(10)…, use Check a barcode instead.
Are my numbers stored?
No. The calculation runs entirely in your browser and nothing is sent anywhere.
What (01), (17) or (10) stand for is listed in the GS1 AI database.