Scan & Generate
Free Barcode Lookup & Validator
Enter a barcode number to validate its format and check digit. Supports EAN-13, UPC-A, ISBN, and more.
Enter digits only (no spaces or dashes)
Supported Barcode Formats
EAN-13
13-digit European Article Number. The most widely used barcode standard for retail products worldwide.
Example: 5901234123457
EAN-8
8-digit compact version of EAN-13. Used for small products where space is limited.
Example: 96385074
UPC-A
12-digit Universal Product Code. Standard barcode in the United States and Canada.
Example: 042100005264
ISBN-13 / ISBN-10
International Standard Book Number. Used to uniquely identify books and publications.
Example: 9780306406157 or 0306406152
GTIN-14
14-digit Global Trade Item Number. Used for trade items and case codes in logistics.
Example: 10012345678902
UPC-E
6 or 8-digit compressed version of UPC-A. Used on very small packages.
Example: 04252614
How Barcode Check Digits Work
Most barcode formats include a check digit — the last digit in the barcode — that helps verify the barcode was scanned or entered correctly. It's calculated from the other digits using a specific algorithm.
EAN/UPC Check Digit Algorithm
- Starting from the right (excluding the check digit), alternate between multiplying by 3 and 1
- Sum all the products
- The check digit is the number needed to round the sum up to the nearest multiple of 10
For example, for EAN-13 code 5901234123457:
- Multiply alternating digits: 5×1 + 9×3 + 0×1 + 1×3 + 2×1 + 3×3 + 4×1 + 1×3 + 2×1 + 3×3 + 4×1 + 5×3 = 5+27+0+3+2+9+4+3+2+9+4+15 = 83
- Check digit: 10 - (83 mod 10) = 10 - 3 = 7 ✓
Frequently Asked Questions
What is a barcode check digit?
The check digit is the final digit of an EAN, UPC, ISBN, or GTIN number. It is calculated from all the preceding digits using a weighted sum, so a single mistyped or misread digit produces a number that fails the check. It guards against transcription errors — it does not prove the product exists.
How is the EAN-13 check digit calculated?
Take the first 12 digits and multiply them alternately by 1 and 3, starting with 1 at the left. Add the results, then subtract that total from the next multiple of ten. For 590123412345 the weighted sum is 83, the next multiple of ten is 90, so the check digit is 7 — giving the complete number 5901234123457.
Why does my valid barcode show as invalid?
The usual causes are a missing leading zero (a UPC-A number pasted into an EAN-13 field needs a zero in front), extra spaces or hyphens, or a digit misread from a blurry photo. Check the length first: EAN-13 is 13 digits, UPC-A is 12, EAN-8 is 8, and GTIN-14 is 14.
Does a valid check digit mean the product is real?
No. A valid check digit only means the number is internally consistent. Confirming that a GTIN is registered to a real company and product requires a lookup against the GS1 registry or the brand owner.
What is the difference between a GTIN, an EAN, and a UPC?
GTIN is the umbrella term for GS1 trade item numbers. EAN-13, UPC-A, EAN-8, and GTIN-14 are all GTINs at different lengths. A UPC-A can be expressed as a GTIN-13 by adding a leading zero, which is why the same product can appear under two different-looking numbers.
Is my barcode number sent anywhere?
No. Validation is arithmetic performed in your browser, so the number you enter never leaves your device.
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