Introduction
EAN, ASIN, GTIN and UPC codes play a crucial role in the realm of e-commerce. These codes are not merely numerical identifiers but essential tools for ensuring inventory organisation, product tracking, and seamless integration with marketplaces. Understanding their purpose, functionality, and significance can make the difference between success and failure in an online store.
This article delves into the details of these codes, their applications, and how they can enhance your online sales.
What are EAN, ASIN, GTIN and UPC Codes?
EAN (European Article Number)
EAN, or European Article Number, is a globally recognised barcode format. Initially developed for the European market, it has since become an international standard. EAN codes typically have 13 digits, structured as follows:
- Country prefix (3 digits): Identifies the country of the manufacturer. For Portugal, the assigned prefix is 560, used for all products manufactured or distributed in the country.
- Manufacturer code (4-5 digits): Specifies the producer.
- Product code (5 digits): Uniquely identifies each product.
- Check digit (1 digit): Ensures the code’s validity.

ASIN (Amazon Standard Identification Number)
ASIN is exclusive to Amazon and serves as a unique identifier for products on its platform. It consists of 10 alphanumeric characters, automatically assigned by Amazon during product registration. While ASIN is specific to Amazon, it often links to other codes like EAN or UPC for compatibility.
GTIN (Global Trade Item Number)
GTIN is an overarching system that encompasses other barcode formats, including EAN and UPC. It varies in length and is used globally to uniquely identify trade items. Key formats include:
- GTIN-8: For small items, such as cosmetics.
- GTIN-12: Forms the basis of UPC codes.
- GTIN-13: Forms the basis of EAN codes.
- GTIN-14: For larger packages or product groupings.
UPC (Universal Product Code)
UPC is predominantly used in North America. It comprises 12 digits, structured as follows:
- Manufacturer code (6-10 digits).
- Product code (2-5 digits).
- Check digit (1 digit).
What Are Their Purposes and Differences?
Main Functions
- Unique identification of products.
- Standardisation of inventory and catalogues.
- Facilitates traceability across supply chains.
- Enables integration with marketplaces and management systems.
Key Differences
Feature | EAN | ASIN | GTIN | UPC |
---|---|---|---|---|
Meaning | European Article Number | Amazon Standard Identification Number | Global Trade Item Number | Universal Product Code |
Primary Usage | Europe and globally | Amazon | Global | North America |
Number of Digits | 13 | 10 | 8-14 | 12 |
Application Area | General product identification | Exclusive to Amazon | Encompasses EAN and UPC | General product identification |
Example | 1234567890123 | B01N4O4XH6 | 0123456789012 | 123456789012 |
Practical Example
Imagine you have a product with a UPC code in the United States. To sell it in Europe, you can convert this code into an EAN by adding a leading “0”, making it compatible with European systems.
Why Are They Important and Where to Obtain Them?
Importance of Codes
- Organisation: Codes help maintain well-structured inventories, especially for stores with extensive product ranges. It’s essential in a good fulfilment flow.
- Customer Trust: Properly documented codes inspire greater confidence among buyers.
- SEO and Visibility: Many marketplaces use codes as ranking factors to improve product discoverability.

Where to Obtain?
- EAN and GTIN: Available through GS1. Costs for small businesses range from €50 to €100 per year, increasing with the number of codes and company size.
- UPC: Obtainable via GS1 US, with similar pricing to EAN codes, though initial registration fees may range between $150 and $250.
- ASIN: Automatically generated by Amazon when a product is listed, incurring no additional direct cost.
Economical Alternatives
- Code Resellers: Third-party vendors offer EAN and UPC codes at lower prices, typically €5 to €20 per code. However, verifying their authenticity and marketplace acceptance is crucial.
- Custom Identifiers: Platforms like Etsy and eBay permit the use of internal identifiers for unique or handmade products, bypassing the need for global codes.
The Connection Between These Codes and Online Sales
Major E-commerce Players
- Amazon:
- ASIN is mandatory for all products listed on the platform.
- GTIN codes are required for new listings, except in certain categories.
- eBay and Walmart:
- Require EAN or UPC codes for product listings.
- Worten and FNAC:
- Portuguese retailers that use EAN and UPC codes for product identification in their online and physical stores.
- Alibaba and Temu:
- Global marketplaces leveraging GTIN codes to facilitate international trade and ensure product traceability.
SEO and Product Search
EAN and UPC codes enhance marketplace search algorithms. Correctly coded products are more likely to appear prominently in search results.
Integration with ERP Systems
GTIN codes simplify integration between e-commerce platforms and ERP systems, streamlining inventory management and logistics.

Printing Standards and Best Practices
Proper barcode printing ensures readability and compatibility with scanners in physical stores and logistics centres. Adhering to international standards is essential:
General Standards
- Size: Barcodes should have width-to-height proportions suitable for efficient scanning. Recommended dimensions are 37.29 mm x 25.93 mm for EAN-13.
- Resolution: A minimum printing quality of 300 dpi is required to ensure legibility.
- Contrast: High contrast between the barcode and its background is essential, typically black on white.
Specific Requirements by Code
- EAN: Must include a “quiet zone” (blank space) of at least 2.31 mm around the code.
- UPC: Requires proportional spacing, similar to EAN.
- GTIN: Adheres to the same proportions as EAN or UPC, depending on the format (8, 12, 13, or 14 digits).
Printing Materials
- Labels or Adhesive Paper: Resistant to moisture and temperature fluctuations.
- Ink: Use high-quality ink to prevent fading.
Quality Testing
Before deployment, it is advisable to:
- Test the barcode’s readability with various scanners.
- Verify proper alignment on labels or packaging.
Conclusion
EAN, ASIN, GTIN, and UPC codes are indispensable for the effective management and success of e-commerce businesses. These codes enable seamless organisation, traceability, and operational efficiency across the supply chain. By understanding their functionality and applying them correctly, businesses can build customer trust and optimise inventory processes. Furthermore, they are vital for achieving prominence on global marketplaces.
We recommend that entrepreneurs invest in internationally recognised code systems and follow good practices for their implementation and printing. This not only facilitates integration with marketplaces, but also guarantees smooth operation in terms of logistics.

If you’re thinking of internationalising your business via e-commerce, it’s important to be aware of the requirements for selling on marketplaces. The GTIN-EAN is one of them. You can find out more about this on the AICEP website.
Investing in internationally recognised coding systems and adhering to best practices for their implementation ensures smooth integration with marketplaces and logistics operations. With proper knowledge and application, these codes empower businesses to remain competitive, efficient, and ready for growth.
FAQs about EAN, ASIN, GTIN and UPC Codes
Is it mandatory to have an EAN code to sell online?
Yes, most marketplaces like Amazon, eBay, or FNAC require an EAN or GTIN code for product identification. If you only sell in your shop, it’s not mandatory, although it can be a good practice
Can I generate my own EAN code?
No, it is recommended to obtain codes from GS1, the official body that provides globally recognised unique codes.
What is the difference between UPC and EAN codes?
UPC codes are primarily used in North America and have 12 digits, whereas EAN codes are used globally and have 13 digits. Both are part of the GTIN system.
How can I verify if my code is correct?
You can validate the code using online verification tools or specific scanners to ensure that the format and digits are correct. EAN, ASIN, GTIN and UPC are fundamental to success in e-commerce. Understanding their differences, applications and importance is essential for maximising sales and ensuring a professional presence on marketplaces. Invest in acquiring the right codes and benefit from more efficient management and greater visibility for your products.