UPC-A Checksum Calculator - Free, Instant, In Your Browser
Enter the first 11 digits of a UPC-A barcode (or all 12 to validate) to compute its check digit.
How to use UPC A Checksum Calculator
- 1Paste your text or data into the input box above.
- 2UPC A Checksum Calculator runs instantly, right in your browser.
- 3Copy the result or use it directly.
Your file is processed in your browser and is never uploaded.
Frequently Asked Questions
What's the formula?
Each of the first 11 digits is weighted 3 or 1 alternately (odd positions x3), summed, and the check digit is whatever brings that sum to the next multiple of 10.
Is my data sent to a server?
No - everything runs entirely in your browser with JavaScript. Nothing is uploaded.