What is the difference between EAN-13 and UPC-A?

EAN-13 is the global standard (13 digits). UPC-A is the North-American retail standard (12 digits). UPC-A is equivalent to EAN-13 with a leading "0" — every modern scanner reads both as the same GTIN.

Global Trade Item Number — the 14-digit canonical product identifier that subsumes EAN-13, UPC-A, and ITF-14. Stored systems often pad shorter codes with leading zeros to make every product 14 digits.

When should I use Code 128 vs EAN?

EAN/UPC for retail products with a registered GTIN. Code 128 for logistics labels (shipping cartons, internal warehouse barcodes) where the data is arbitrary alphanumeric.

How accurate is the check-digit math?

Exact arithmetic on GS1 modulo-10 — the canonical algorithm published in GS1 General Specifications §7.9. Every retail POS computes it the same way.

What is the difference between EAN-13 and UPC-A?

EAN-13 is the global standard (13 digits). UPC-A is the North-American retail standard (12 digits). UPC-A is equivalent to EAN-13 with a leading "0" — every modern scanner reads both as the same GTIN.

Global Trade Item Number — the 14-digit canonical product identifier that subsumes EAN-13, UPC-A, and ITF-14. Stored systems often pad shorter codes with leading zeros to make every product 14 digits.

When should I use Code 128 vs EAN?

EAN/UPC for retail products with a registered GTIN. Code 128 for logistics labels (shipping cartons, internal warehouse barcodes) where the data is arbitrary alphanumeric.

How accurate is the check-digit math?

Exact arithmetic on GS1 modulo-10 — the canonical algorithm published in GS1 General Specifications §7.9. Every retail POS computes it the same way.

Barcode Validator (EAN-13 / UPC-A / Code 128)

Validate a barcode number, compute the check digit, and produce a ready-to-render image URL. Supports EAN-13, EAN-8, UPC-A, Code 128, and ISBN.

Result

EAN13 — computed check digit

978014017739·8

Append the highlighted check digit to make the barcode valid.

Canonical form9780140177398
Check digit8
Render linkOpen in a browser to preview the visual barcode.https://barcodeapi.org/api/ean13/9780140177398
GTIN-equivalentEAN-13/UPC-A stored as 14-digit GTIN with a leading 0 for UPC-A.9780140177398

Source: GS1 General Specifications v25 (2026) §7.9 — GTIN check-digit calculation.

Note — Preview URL hits an external rendering service (barcodeapi.org). For privacy-sensitive payloads use a local library (bwip-js, JsBarcode).

Step-by-step

Body digits: 978014017739 (12 digits).
Apply GS1 modulo-10: weights alternate 3,1,3,1… from the right of the body.
check digit = (10 − sum mod 10) mod 10 = 8.

How to use this calculator

Pick the symbology your barcode is in.
Enter the data — with or without the check digit.
Read the canonical form and the computed/validated check digit.
Copy the render link to a browser to preview the barcode image.

About this calculator

Every retail product barcode in the world has a check digit at the end — a single digit chosen so the GS1 modulo-10 weighted sum lands on a multiple of 10. This tool computes that check digit for the symbologies you actually run into: EAN-13 (the global standard), EAN-8 (small packages), UPC-A (US/Canada retail), ISBN-13 (books), and Code 128 (any ASCII, used in shipping labels). Type the data digits and the tool gives you the canonical form, the check digit, and a ready-to-render preview URL. Type a complete barcode and the tool tells you whether the check digit is correct.

How it works — the formula

sum = Σ(digit_i · w_i), where w_i alternates {3,1} from right
check_digit = (10 − sum mod 10) mod 10

GS1 modulo-10: a weighted sum where adjacent digits weight 3 vs 1, then the check completes the multiple of 10. Catches single-digit errors and most transposition errors.

Sources: GS1 General Specifications v25 §7.9 · ISO/IEC 15420:2009 — EAN/UPC bar code symbology · ISO/IEC 15417:2007 — Code 128 bar code symbology

Worked examples

Example 1

EAN-13 body 012345678901

Inputs:: data=012345678901, sym=ean13
Output:: check digit 2 → 0123456789012

Example 2

UPC-A 03600029145

Inputs:: data=03600029145, sym=upca
Output:: check digit 2 → 036000291452

Example 3

ISBN-13 9780140177398

Inputs:: data=9780140177398, sym=isbn
Output:: valid (Penguin Classics)

Limitations

No visual rendering inline — preview link points to barcodeapi.org.
Code 128 acceptance is permissive (any printable ASCII).
Does not check whether a real product is registered under the GTIN.

Check-digit calculation is exact; canonical industry algorithm.

Frequently asked

A single digit appended to the data digits so the weighted-sum modulo 10 is zero. For EAN/UPC/ISBN-13 the weights alternate 1 and 3 from the right. It is error-detection, not encryption.