Compute or verify the check digit for EAN-13, UPC-A and EAN-8 barcodes, mod-10 weighting with the odd and even positions, browser-only
- Runs locally
- Category Developer & DevOps
- Best for Checking file type, size, metadata, and obvious mismatch signals before sharing.
Enter digits above to see the result.
What this tool does
Free EAN / UPC check digit calculator that computes and verifies the last digit of EAN-13, UPC-A and EAN-8 retail barcodes. Every GS1 barcode ends in a check digit derived from the digits before it: read each digit from the right, multiply by 3 and 1 alternately, sum the products, and the check digit is whatever brings that sum up to the next multiple of ten. Paste a body without its last digit and the tool returns the digit you need, then prints the completed barcode ready to copy. Paste a full code and it tells you pass or fail, so a mistyped number gets caught before it reaches a label printer or a product feed. Length picks the symbology for you: twelve body digits means EAN-13, eleven means UPC-A, seven means EAN-8. Spaces and hyphens are ignored on input. Everything runs in your browser with one-click copy and a shareable link, no upload and no GS1 account.
Tool details
- Input
- Form fields
- The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
- Output
- Live result + Copy
- The result area focuses on usable output, with copy, download, or preview actions when supported.
- Privacy
- Browser-side processing
- The main tool logic does not call an external API, so inputs normally stay in the current tab.
- Save / share
- Shareable URL state
- Key settings are encoded in the URL so another person can reopen the same setup.
- Performance budget
- Initial JS <= 9 KB
- No WASM budget is declared, keeping the tool quick to open on mobile.
- Best fit
- Developer & DevOps · Developer
- Category and role tags drive related tools, internal links, and quick fit checks.
How to use
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1. Input
Paste or drop your content into the tool panel.
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2. Process
Click the button. All processing is local in your browser.
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3. Copy / Download
Copy the result or download to disk in one click.
How EAN / UPC Check Digit Calculator fits into your work
Use it before upload, handoff, archive, support review, or any moment where a file needs one local check before it leaves your machine.
File jobs
- Checking file type, size, metadata, and obvious mismatch signals before sharing.
- Preparing mixed folders for upload, archive, intake, or review.
- Keeping sensitive files in the browser instead of sending them to an account-based service.
File checks
- Do not treat the extension alone as proof of the real file type.
- Review metadata before a file goes to customers, vendors, or a public page.
- Keep the original file until the copied, converted, or exported result is verified.
Good next steps
These links move the current task into a more complete workflow.
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- 3 Barcode Generator Code 128 / EAN-13 / UPC-A / Code 39 — generate scannable 1D barcodes, export SVG or PNG, fully offline. Open
FAQ
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