EAN-13 Check Digit Calculator
Find the 13th check digit from the first 12 EAN digits.
What it does
EAN-13 barcodes end with a check digit that catches misreads. Scanners weight the first 12 digits, sum them, and derive the 13th. A wrong check means a damaged label or a typo, not a valid product code.
The tool above takes the first 12 digits and returns check digit, full 13 digit code, and weighted sum. The defaults 590123412345 match the worked example, so the page opens showing check 7. Type new digits to update all three results.
Weights run from the left: positions 1, 3, 5, 7, 9, 11 count once, positions 2, 4, 6, 8, 10, 12 count three times. Add those products for the sum. Check is (10 minus sum mod 10) mod 10, so a sum ending in 0 gives check 0.
This checks arithmetic only. It never proves GS1 registration or country assignment. Prefixes need a GS1 license, and printed bars need quiet zones and sizing for reliable scans.
This page shows the formula, one full hand checked example at 590123412345, a reference table, and practice checks that run through the tool.
How to use
- Type the first 12 digits. Dashes and spaces strip out.
- Check that length is exactly 12 digits or the tool reports an error.
- Read Check digit as the single 13th number.
- Read Full EAN-13 as your 12 plus the check.
- Read Weighted sum for records and debugging.
- Register prefixes with GS1 separately. Pass here is math only.
Formula
- odds
- Digits 1,3,5,7,9,11 from the left, times 1.
- evens
- Digits 2,4,6,8,10,12 from the left, times 3.
- check
- 13th digit appended to the 12.
EAN-13 uses 1/3 weights from the left. UPC-A uses 3/1 weights on 11 digits, so the two are not interchangeable. Non digits stop the tool with a message.
Worked example
Example: 590123412345
Find the check for first 12 digits 590123412345.
- Odds: 5+0+2+4+2+4 = 17.
- Evens: 9+1+3+1+3+5 = 22, times 3 = 66.
- Sum: 17 + 66 = 83.
- Mod: 83 mod 10 = 3.
- Check: (10 minus 3) mod 10 = 7.
- Full: 5901234123457.
Reference table
| First 12 | Sum | Full 13 |
|---|---|---|
| 590123412345 | 83 | 5901234123457 |
| 400638133393 | 89 | 4006381333931 |
| 123456789012 | 92 | 1234567890128 |
Limits
- Arithmetic only. No registry or country proof.
- 12 digits to start. 13 digit inputs are rejected.
- Print quality, size, and quiet zones sit outside.
- UPC, ISBN, and EAN-8 use different rules.
Common mistakes
- Weighting from the right instead of the left.
- Using UPC 3/1 weights for EAN-13 1/3 order.
- Pasting the check digit as part of the 12.
- Leaving spaces that change length. This tool strips them first.
- Assuming pass means GS1 licensed.
Try it yourself
Quick checks. Answers sit tucked under each question.
Check for 400638133393?
Sum 89, check 1, full 4006381333931.
Check for 123456789012?
Sum 92, check 8, full 1234567890128.
Questions
How is EAN-13 check figured?
Odds once plus evens three times, then (10 minus sum mod 10) mod 10.
What is full EAN-13 here?
Your 12 plus the check. Here 5901234123457.
EAN-13 or UPC?
EAN-13 is 13 digits with 1/3 weights. UPC-A is 12 digits with 3/1 weights.
Can I paste dashes?
Yes. Dashes and spaces strip before math.
Does pass mean registered?
No. Arithmetic only, never GS1 assignment.
Why 12 digits in?
The 13th is derived. Enter the first 12 to compute it.