Generating barcodes for your products starts with one key decision: whether your products will be sold through retail channels or tracked only within your own business. Retail barcodes require a registered number from GS1, the global organization that manages product identification. Internal barcodes for warehouse or inventory tracking can be created for free using online tools. Here’s how both paths work.
Retail vs. Internal Barcodes
If your product will appear on a store shelf, in an online marketplace like Amazon, or anywhere a point-of-sale scanner needs to read it, you need a standardized barcode tied to a globally unique number called a GTIN (Global Trade Item Number). This is the 13-digit number encoded in the familiar striped barcode on every consumer product. Retailers, distributors, and marketplaces require GTINs because they prevent conflicts. No two products anywhere in the world share the same number.
If you only need barcodes to track inventory inside your own warehouse, manage stock between locations, or label items for internal use, you can skip the registration process entirely. You assign your own numbers, generate barcodes with a free tool, print them, and start scanning. The key distinction is that these internal barcodes mean nothing outside your business.
How to Get a GS1 Number for Retail
Every retail barcode starts with a GS1 Company Prefix, which is a string of digits licensed to your business. You combine this prefix with an item reference number you assign to each product, and a final check digit calculated automatically. Together, these form the 13-digit GTIN that gets encoded into your barcode.
To register, go to GS1 US (or your country’s GS1 office) and choose a plan based on how many products you need to barcode. Current GS1 US pricing:
- 1 product: $30 one-time fee, no annual renewal
- Up to 10 products: $250 initial, $50/year renewal
- Up to 100 products: $750 initial, $150/year renewal
- Up to 1,000 products: $2,500 initial, $500/year renewal
- Up to 10,000 products: $6,500 initial, $1,300/year renewal
- Up to 100,000 products: $10,500 initial, $2,100/year renewal
If you sell just one product, the single GTIN option at $30 with no renewal is hard to beat. For growing product lines, the 10-product tier gives you room to expand without a large upfront cost. Once registered, you assign item reference numbers sequentially starting from zero. Don’t try to encode meaning into the numbers (like using “100” for one category and “200” for another). Sequential numbering keeps things simple and avoids gaps that cause confusion later.
After combining your prefix with your item reference, use GS1’s free check digit calculator to generate the final digit. That completes your GTIN.
Choosing the Right Barcode Type
The barcode type (called a “symbology”) determines how your number gets translated into the pattern of black and white bars. For consumer products, you’ll almost always use one of two formats:
- EAN-13: The international standard for retail products. It encodes 13 digits and is used worldwide, including at point-of-sale terminals.
- UPC-A: The most common format on consumer goods in the United States. It encodes 12 digits and is technically a subset of EAN-13.
If your product will sell in U.S. stores, UPC-A is the default. For international distribution, EAN-13 covers you globally. Most barcode generators let you pick either format.
Two other symbologies come up in specific contexts. Code 128 is widely used in distribution, food, and medical industries for shipping labels and case-level identification. ITF (Interleaved 2 of 5) is the standard for outer cartons and distribution packaging. Neither of these belongs on the consumer-facing label of a retail product, but if you’re shipping cases to a warehouse or distributor, you may need them in addition to your product barcode.
Generating the Barcode Image
Once you have your GTIN, you need to turn it into a scannable image. Several free online tools handle this. Zoho’s barcode generator, for example, lets you select the barcode type (EAN-13, UPC-A, Code 39, or ITF), enter your number, optionally add a title and note, and download the barcode image. The process takes about 30 seconds.
GS1 also provides barcode generation tools as part of your membership. If you’re using inventory or e-commerce software like Shopify, WooCommerce, or a warehouse management system, many of these platforms have built-in barcode generation that pulls directly from your product catalog.
For internal-only barcodes, the process is even simpler. You create your own numbering system (or use your existing SKU numbers), plug them into a free generator, and download the images. An SKU is the alphanumeric code you assign internally for tracking. Unlike a GTIN, it doesn’t need to be registered or globally unique.
Printing Barcodes That Actually Scan
A barcode is useless if a scanner can’t read it, and print quality is where many businesses run into trouble. Standard inkjet and laser printers produce barcodes at varying DPI (dots per inch) resolutions, which can distort the precise bar widths that scanners rely on. For occasional printing of a few labels, a laser printer on high-quality settings can work. But if barcodes are a regular part of your operations, a thermal transfer printer is worth the investment.
Thermal printers are built specifically for barcode printing. They operate at fixed DPI settings designed for high accuracy, and they print on rolls of individual labels rather than full sheets. This means you can print one label or a thousand without waste. Thermal labels also come in a wide range of materials, from standard paper to chemical-resistant synthetics, so you can match the label to your product’s environment. A barcode on a frozen food item, a chemical container, or an outdoor product needs to survive moisture, cold, or UV exposure. Inkjet and laser printers offer almost no flexibility in label material or ink durability.
Entry-level thermal label printers designed for barcode printing start around $150 to $300. For a small business printing labels in-house, a basic thermal printer paired with compatible label rolls will pay for itself quickly in reliability and reduced reprints.
Sizing and Placement on Packaging
Retailers have specific requirements for barcode placement. The barcode should appear on a flat, smooth surface of the packaging where it won’t be folded, creased, or obscured by seams. For most products, the back or bottom panel is standard. The minimum size for a UPC-A barcode is roughly 1.02 inches wide by 0.82 inches tall, though GS1 publishes detailed sizing guidelines based on your packaging dimensions.
Leave a clear “quiet zone” of empty white space on both sides of the barcode. This margin is what tells the scanner where the barcode starts and stops. Without adequate quiet zones, even a perfectly printed barcode will fail to scan. The minimum quiet zone is typically about 0.25 inches on each side, but more space is better.
Print the barcode in black bars on a white background for the best contrast and scan reliability. Dark blue or dark green bars can also work, but avoid red, orange, or yellow for the bars, as many scanners use red light and won’t detect those colors. Similarly, avoid reflective or glossy surfaces directly over the barcode area.
What to Do Before Selling
Before your product ships to a retailer or goes live on a marketplace, test your barcode with an actual scanner. Many smartphones can scan barcodes using free apps, which gives you a quick sanity check that the number encoded matches your GTIN. For retail compliance, a dedicated barcode verifier (different from a simple scanner) grades the print quality and confirms the barcode meets GS1 standards. Some print shops and fulfillment centers offer verification as a service.
If you’re selling on Amazon, Walmart Marketplace, or similar platforms, you’ll typically enter your GTIN during product listing setup. The platform uses that number to identify your product in its catalog. Having a properly registered GS1 number prevents listing errors and avoids the risk of your barcode conflicting with another product.