Media
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Description
Calculate or verify the GS1 check digit for EAN-13, EAN-8, UPC-A and ITF-14 / GTIN-14 codes. Runs entirely on your device. Paste a code into the toolbar popup and get an answer, without opening another tab. WHAT IT DOES • Four symbologies: EAN-13 / GTIN-13, EAN-8 / GTIN-8, UPC-A / GTIN-12, ITF-14 / GTIN-14 / SCC-14 • Payload in, check digit out — works from 12, 7, 11 or 13 digits • Full code in, valid or not out, and when it is wrong the popup names the exact position: "position 14 should be 2, you entered 5" • One-click repair when a single wrong digit explains the failure • GTIN-13 ↔ GTIN-14 conversion with a packaging indicator from 0 to 9 • Copy buttons for both results HOW IT WORKS The check digit is a GS1 mod-10 sum: working left from the check digit, digits get weight 3 and 1 in alternation, then the total is subtracted from the next multiple of ten. This extension implements that in the popup. PRIVACY Everything runs on your device. The extension asks for no permissions, makes no network requests and stores nothing. What you type stays in the popup. MORE Full web tools, including a bulk generator for up to 100 codes from a CSV: https://gtin14.com Check digit calculator page: https://gtin14.com/check-digit-calculator/ Open source (MIT): https://github.com/larrygofast89/gtin14-check-digit Not affiliated with GS1 AISBL.