TL;DR: Free international barcode validator: ISBN-13/ISBN-10/EAN-13/IMEI in one place — paste and it auto-detects the type, verifying check digits per standard (mod 10 / mod 11 / Luhn) locally, with Bookland prefix parsing for ISBN-13.
This tool runs entirely in your browser. Open DevTools → Network panel and search your input — it appears in no request.
Usage Guide
ISBNs and product barcodes look alike and follow different rules: ISBN-13 is an EAN-13 in the 978/979 Bookland range, ISBN-10 is the legacy standard (mod 11, trailing X allowed), EAN-13 covers everything else, and IMEI is a phone’s identity (Luhn). This tool validates all four in one place — paste and it auto-detects the type, checks the digit per standard, and labels GS1 prefixes. Run it before entering catalog data, verifying shipping lists, or checking device IDs.
1. Four checksum schemes at a glance
ISBN-13/EAN-13 share one scheme: the first 12 digits weigh 1,3 alternately; check = 10 − (sum mod 10). ISBN-10 weighs 10 down to 1 and requires divisibility by 11 — the only family where X appears (remainder 10). IMEI is 15 digits under Luhn (double every second digit from the right, subtract 9 over 9). All four certify self-consistency only — not that an ISBN was ever assigned or an IMEI shipped.
2. How auto-detection draws its lines
Rules: 13 digits starting 978/979 → ISBN-13; any other 13 → EAN-13; 10 digits (trailing X ok) → ISBN-10; 15 → IMEI. The ambiguous case — a book’s EAN form starting 978 — validates identically either way since the schemes coincide. Generated test codes use public example ranges (EAN 2xx in-store range, card-network test bins) and cannot hit real products or devices.