TetraKits
Every product on a retail shelf, in a warehouse bin, or listed on a marketplace relies on scannable identifiers. Barcodes translate SKUs and global trade numbers into lines a laser or imager reads in milliseconds. If you manufacture goods, sell private-label products, or manage inventory for a growing shop, you need barcodes that scan correctly the first time — every time.
This guide explains how to generate product barcodes online with the free TetraKits Barcode Generator, which formats to choose (EAN-13, UPC-A, CODE128, CODE39), how retail and Amazon workflows differ, and how to prepare labels that pass checkout scanners.
Why product barcodes matter
Barcodes reduce human error at scale. Cashiers do not re-type prices; warehouse staff confirm pick locations; marketplaces match listings to physical shipments. A bad barcode — wrong format, invalid check digit, or smudged print — causes chargebacks, listing suspensions, and frustrated customers.
Small businesses sometimes delay barcoding until the first big retailer meeting. That is risky. Assign identifiers early, test scans on real hardware, and keep artwork vector-sharp so growth does not force a costly relabeling project.
Linear vs. 2D codes
Product checkout overwhelmingly uses linear barcodes (EAN, UPC, CODE128). QR codes are two-dimensional and better for consumer marketing links. Packaging often carries both: a linear barcode for POS systems and a QR code for manuals or promotions.
EAN, UPC, CODE128, and more
Choosing the wrong symbology is the fastest way to produce unscannable labels. Match the format to your channel and geography.
EAN-13
EAN-13 is the global retail standard outside North America. It encodes 12 data digits plus a check digit, often represented as 13 digits total. You need a valid GS1-issued company prefix for official retail use; the Barcode Generator renders the symbol from the number you provide.
UPC-A
UPC-A dominates North American retail with 12 digits. Marketplaces like Amazon US frequently expect UPC identifiers on new ASINs. Again, legitimate retail distribution requires proper GS1 registration — the generator visualizes the barcode from your valid code.
CODE128
CODE128 encodes alphanumeric data densely and is popular for internal SKUs, cartons, shipping labels, and warehouse racks. It does not replace GS1 retail numbers on consumer units headed to major chains, but it excels when you control the entire scanning workflow.
CODE39
CODE39 supports letters and numbers with simpler encoding rules. Logistics teams and older scanners still use it for internal asset tags. Verify compatibility with your scanners before mass printing.
EAN-8 and compact formats
Small packages with limited space may use EAN-8. Confirm retailer acceptance before switching from EAN-13.
Retail and Amazon requirements
Retailers and marketplaces validate identifiers against databases. A pretty barcode image is not enough if the number is invalid or already assigned to another product.
GS1 company prefixes
For mainstream retail, purchase a GS1 company prefix and allocate GTINs properly. Keep a master spreadsheet mapping products to numbers. Never invent “random” UPCs for national retail — those scans fail validation at distributors.
Amazon and online marketplaces
Amazon listing workflows typically require a GTIN (UPC, EAN, ISBN, etc.) for branded or new products. The barcode on your packaging must match the identifier in the listing exactly. Test scans with a handheld imager before FBA inbound shipments to avoid relabel fees.
Internal and direct-to-consumer sales
If you sell only on your website or local markets without GTIN mandates, CODE128 internal SKUs may suffice for inventory. Upgrade to GS1 numbers before approaching big-box buyers.
Step-by-step: generate a product barcode
- Obtain a valid product number for your channel — GS1 GTIN for retail marketplaces or an internal SKU string for CODE128 warehouse labels.
- Open the TetraKits Barcode Generator. Processing runs in your browser; codes are not uploaded to a server.
- Select the symbology that matches your requirement: EAN-13, UPC-A, CODE128, CODE39, or EAN-8.
- Enter the data exactly, including check digits where applicable. The tool validates structure for standard formats.
- Adjust dimensions: bar height, module width, and quiet zones affect scan reliability.
- Customize colors cautiously. Dark bars on light backgrounds scan best; reverse printing needs verification on target hardware.
- Download PNG for quick labels or SVG for professional print. Vector formats prevent jagged edges on packaging dies.
- Print a test sheet and scan with the same devices used at checkout or in your warehouse.
Label design and printing
Barcode generation is half the battle; label execution determines scan rates.
Quiet zones and placement
Leave blank margin on both sides of the symbol — scanners need clear space to detect edges. Do not truncate bars when cropping label artwork.
Human-readable text
Print the digits below the bars for manual verification when scans fail. Match the text to the encoded data exactly.
Material and finish
Glossy lamination and metallic foils can glare under laser scanners. Matte finishes and sufficient bar height improve first-pass read rates.
Label sizes
Tiny products need compact symbologies (EAN-8) or shortened CODE128 payloads. Oversized cartons benefit from larger bar height for distance scanning on conveyor lines.
Pairing barcodes with QR codes
Modern packaging communicates at two speeds: the checkout beep of a UPC/EAN and the marketing click of a QR code linking to recipes, registration, or sustainability info. Generate linear barcodes in the Barcode Generator and consumer QR codes in the QR Code Generator — same site, consistent privacy model, no per-label fees.
Product barcodes are infrastructure, not decoration. Choose the correct symbology, source legitimate GTINs for retail, test on real scanners, and export vector artwork for crisp labels. TetraKits gives you production-ready barcodes in seconds so you can focus on products customers actually want to buy.
Frequently asked questions
Can I generate a UPC barcode for free?
Yes. TetraKits Barcode Generator creates UPC-A images for free in your browser. You must still obtain a valid UPC number from GS1 or an authorized source for legitimate retail use — the generator renders the symbol from the number you supply.
What is the difference between EAN-13 and UPC-A?
Both identify products at retail checkout. UPC-A is standard in North America (12 digits). EAN-13 is common internationally (13 digits). Many scanners read both; choose based on marketplace and retailer requirements.
When should I use CODE128 instead of UPC?
Use CODE128 for internal warehouse labels, cartons, and alphanumeric SKUs you control end-to-end. Consumer products sold through major retail need GS1-backed UPC or EAN identifiers instead.
Will Amazon accept barcodes created online?
Amazon validates the GTIN itself, not which tool drew the bars. Your listing identifier must match the barcode on packaging, and the GTIN must be legitimate for the brand and product.
PNG or SVG for product labels?
Use SVG (or EPS) for professional print vendors and packaging runs. PNG works for small batches and office label printers when exported at sufficient resolution.
