Barcode Lookup & Validators

About the Lookup & Validator Tools

These tools cover the boring-but-essential second half of a barcode workflow: confirming that the value you scanned, OCR'd or were sent is a real, well-formed identifier — and finishing the value when it's incomplete. Every tool runs in your browser. There is no third-party product database call: we validate the structure (length, character set, country prefix, mod-10 check digit) that the value itself encodes.

Need to look up actual product data behind a verified GTIN? Pair the validator with the wholesaler / retailer feed you're already licensed for. Need to read a barcode first, or generate a new one from a verified value? The reader and generator hubs have you covered.

When to Use It

• Confirming a 12- or 13-digit barcode from a supplier feed before sending it to print.
• Validating an ISBN supplied by an author or distributor against the GS1 mod-10 / ISO 2108 mod-11 rules.
• Computing the final check digit for a partial GTIN body you pulled out of a planning spreadsheet.
• Triaging an unknown barcode value pulled from a CSV export and figuring out which symbology to expect.
• Cross-checking a UPC-A on a US retail item against the same product's EAN-13 export listing.
• Round-trip-verifying a barcode you just generated — read it back and validate the value with the matching tool.

How It Works

1. Paste a value Each tool accepts the raw digits from a scan, a screenshot OCR, a supplier feed or a label-artwork file.
2. Pick the right tool Use the detector if you don't know the format; a format-specific lookup (UPC / EAN / ISBN) when you do; the GTIN validator for cross-format.
3. Read the verdict Tools return validity (pass / fail), the canonical normalised form, the GS1 prefix where it applies, and a one-click copy of the corrected value.
4. Fix or finish If the check digit is wrong, the Check Digit Calculator gives you the right one. If the format is wrong, the detector tells you what it actually looks like.
5. Hand off Take the validated value into a generator, a retailer feed or your inventory system. The tools never store the values you paste.

What to Avoid

• Don't treat a valid check digit as proof that a product exists — these tools verify structure, not ownership or retail registration.
• Don't strip leading zeros from a UPC-A before validating — the leading zero is one of the 12 required digits.
• Don't pass a GS1 Digital Link URL into the UPC / EAN lookups — use the GS1 Digital Link Decoder instead; the raw URL won't validate as a 12- or 13-digit barcode.
• Don't enter ISBN-10 values into the EAN lookup; ISBN-13 (978 / 979 prefix) is the EAN-13 form — ISBN-10 needs the ISBN reader's mod-11 check.
• Don't assume the Type Detector is authoritative for short numeric values — a 12-digit string could be UPC-A, GTIN-12 or coincidence; verify with the matching validator.

Tips & Tricks

• When triaging a batch of unknown barcodes, run them through the Type Detector first, then route to the matching validator — much faster than guessing per value.
• If the GTIN Validator flags a check-digit mismatch, the Check Digit Calculator will show you what the correct final digit should be, often surfacing a single transposed digit upstream.
• ISBN-13 always starts with 978 or 979 — if you see a 13-digit barcode without that prefix, it's an EAN-13 for a non-book product, not an ISBN.
• GTIN-14 with a leading 0 is just a GTIN-13 (EAN-13) padded with a zero on the left, so both forms share the same check digit.
• Always pair a generator with the matching validator in your QA — generate a code, read it back, validate the value, then sign off the artwork.

How to Check If a Barcode Is Valid

A barcode number is valid when its length fits the format and its last digit matches the check digit calculated from the digits before it.

1. Read the digits printed under the bars, or scan the code with the barcode reader to get them exactly.
2. Count them: 8 for EAN-8, 12 for UPC-A, 13 for EAN-13 or ISBN-13, 14 for GTIN-14, and 10 for ISBN-10.
3. Paste the value into the validator for that format, or into the GTIN validator, a GS1 barcode validator for all four GTIN lengths, if you are not sure which one you have.
4. If the check fails, look for a mistyped or swapped digit before you print or list the code.

This works as a barcode validity checker for any barcode with a check digit in its number. The check digits guide walks through the mod-10 and mod-11 arithmetic. A UPC-A and the EAN-13 formed by adding a leading zero share one check digit, as the UPC vs EAN comparison shows.

Barcode Validation vs Barcode Verification

Validation checks the number; verification grades the printed symbol with a barcode verifier, following ISO/IEC 15416 for linear barcodes and ISO/IEC 15415 for 2D symbols.

A number can pass validation and the printed barcode still fail verification because of low contrast or a symbol printed too small. The GS1 General Specifications set a minimum grade of 1.5 (C) for most retail EAN/UPC symbols.

Frequently Asked Questions