GTIN Check Digit Calculator
Free GTIN check digit calculator: compute or verify the check digit for GTIN-8, GTIN-12, GTIN-13, and GTIN-14. Runs in your browser, no upload.
This GTIN check digit calculator computes the final check digit for a GTIN, or verifies that the one you already have is correct. Paste a single barcode or a column of them — from a supplier feed, an ERP export, or a label proof — and get an instant pass or fail without an account, an upload, or a file-size limit.
GTIN Check Digit Calculator
The interactive version of this tool is coming soon. It will run entirely in your browser — no login, no upload limits.
Planned tool: gtin check digit calculator
Need this now? Talk to ClaroWhat it checks
- Calculates the check digit for a partial number across all four GTIN lengths: GTIN-8, GTIN-12 (UPC-A), GTIN-13 (EAN-13), and GTIN-14 (the shipping/case format with a packaging indicator).
- Verifies an existing check digit by recomputing it from the leading digits and comparing it to the last digit you supplied — flagging any mismatch.
- Validates length and characters, rejecting values that are too short, too long, or contain non-numeric characters (a common symptom of a leading apostrophe or a code stored as text in a spreadsheet).
- Normalizes formatting by stripping spaces, hyphens, and stray separators before the math runs, so a furniture SKU pasted as
0 12345 67890 5is read the same as012345678905. - Returns the corrected, complete GTIN so you can write the right value straight back into your catalog.
How the GTIN check digit calculator works
Every GTIN ends in a single check digit defined by the GS1 General Specifications. It is a deterministic Modulo-10 calculation: read the digits from right to left, multiply alternating positions by 3 and 1, sum the products, and the check digit is the amount needed to round that sum up to the next multiple of 10. Because the rule is fixed, the same input always produces the same result — there is no lookup table and nothing to guess.
All processing happens client-side in your browser. The barcodes you paste never leave your machine, are not uploaded to a server, and are not logged — which matters when you are working with an unreleased CPG launch SKU or a confidential industrial-distribution price file.
| GTIN format | Total digits | Typical use |
|---|---|---|
| GTIN-8 | 8 | Small-pack EAN-8 items where space is tight |
| GTIN-12 | 12 | UPC-A retail items in North America |
| GTIN-13 | 13 | EAN-13 retail items used globally |
| GTIN-14 | 14 | Case, carton, and pallet (MRO and CPG logistics units) |
A correct check digit is necessary but not sufficient. A value can pass the math and still be the wrong identifier for the product — for example, a case GTIN-14 entered where the base unit GTIN-13 belongs. Treat this tool as the first gate in enrichment: confirm the digit, then confirm the identifier means what you think it means.
Related resources
Tool
GTIN / EAN / UPC Validator
Validate full GTIN, EAN, and UPC values in bulk, including length and format checks.
Tool
GS1 Company Prefix Lookup
Check which company prefix a GTIN belongs to once the check digit passes.
Glossary
GTIN vs EAN vs UPC
How the formats relate and when each applies across regions and channels.
Glossary
SKU vs MPN vs GTIN
Tell internal SKUs apart from manufacturer and global trade identifiers.
Guide
Common Barcode Errors in Supplier Feeds
The recurring GTIN mistakes that break listings, and how to catch them at intake.
Claro
Automated catalog enrichment
Validate and correct GTINs at scale with provenance on every field.
FAQ
How do I calculate a GTIN check digit?
Take the digits to the left of the check position, read them right to left, multiply alternating digits by 3 and 1, and add the products. The check digit is whatever you must add to reach the next multiple of 10. The calculator above does this for GTIN-8, GTIN-12, GTIN-13, and GTIN-14 automatically and shows the completed number.
Is the check digit the same for UPC and EAN?
The calculation rule is identical — both use the GS1 Modulo-10 method. The difference is length: a UPC-A is a 12-digit GTIN-12 and an EAN-13 is a 13-digit GTIN-13. Pad a UPC-12 with a leading zero and it becomes a valid GTIN-13. See GTIN vs EAN vs UPC for how the formats line up.
What does it mean if the check digit is wrong?
A failed check digit almost always means a typo: one digit was entered incorrectly, or two were transposed. It can also signal a formatting problem, such as a barcode stored as a number that dropped a leading zero. Recompute the digit from the leading digits, fix the source value, and re-verify — do not simply overwrite the last digit to make it pass.
Does a valid check digit mean the GTIN is real and registered?
No. The check digit only confirms internal arithmetic consistency. It does not confirm the GTIN is licensed to a specific company or that it maps to a real product. To check ownership, look up the GS1 company prefix; to confirm the product, match it against an authoritative catalog record.
Can I check a whole spreadsheet column of GTINs at once?
Yes. Paste a column of values and each row is calculated or verified independently, with no row limit and no upload. For ongoing feeds where new GTINs arrive every day, an automated enrichment pipeline that validates check digits and writes corrections back to the source is more sustainable than re-pasting by hand.