If you sell products — whether on Amazon, in a retail store, or at a weekend market — you need barcodes. They look simple, but choosing the wrong format or entering the wrong number means your product will not scan at checkout. And that is a headache nobody wants.
This guide is written for small business owners and Amazon sellers who need to generate barcodes without paying for expensive software. We cover which barcode format you actually need (spoiler: it depends on where you sell), how the numbers work, common mistakes that make barcodes unscannable, and how to print them correctly.
Generate Barcodes — Free, Print-Ready
EAN-13, UPC, Code 128, Code 39. Download as PNG or SVG instantly.
Which Barcode Format Do You Need?
There are dozens of barcode formats, but you probably only need one of these four:
| Format | Digits | Used For | Where |
|---|---|---|---|
| EAN-13 | 13 | Retail products | Worldwide (except US/Canada) |
| UPC-A | 12 | Retail products | US and Canada |
| Code 128 | Variable | Shipping, logistics, internal use | Everywhere |
| Code 39 | Variable | Manufacturing, military, healthcare | Internal systems |
Quick decision: Selling physical products in stores? Use EAN-13 (or UPC-A if US only). Internal inventory tracking? Use Code 128. It is that simple.
EAN-13 vs UPC-A
These are actually the same system — UPC-A is a subset of EAN-13 with a leading zero. If you have a UPC number, you can convert it to EAN-13 by adding a 0 at the front. Most modern scanners read both formats interchangeably.
How to Generate a Barcode (Step by Step)
- Get your number: For retail products, you need a GS1-registered number (buy from gs1.org or your local GS1 office). For internal use, make up any number.
- Open the generator: Go to ToolsArena Barcode Generator
- Select format: Choose EAN-13, UPC-A, Code 128, or Code 39
- Enter your number: Type or paste the product number. The tool auto-calculates the check digit.
- Download: Get your barcode as PNG (for documents) or SVG (for professional printing).
5 Mistakes That Make Barcodes Unscannable
We see these errors constantly from first-time sellers:
- Wrong format for the market: Using Code 39 for retail products. Retail scanners expect EAN or UPC — anything else gets rejected at checkout.
- Printing too small: EAN-13 barcodes need to be at least 37.29mm wide × 25.93mm tall at 100% magnification. Shrink it below 80% and scanners struggle.
- Low contrast: Barcodes need dark bars on a light background. Black on white is ideal. Avoid dark blue on black, red bars (scanners use red lasers and cannot see red), or bars on busy backgrounds.
- Wrong check digit: Manually typing the check digit instead of letting it auto-calculate. One wrong digit = barcode rejected everywhere.
- Cutting into the quiet zone: The blank space on either side of the barcode is not wasted space — scanners need it to know where the barcode starts and ends. Never crop into it.
How to Print Barcodes Correctly
Generating a barcode is easy. Printing it so it actually scans is where people mess up.
| Factor | Requirement | Why |
|---|---|---|
| Resolution | 300 DPI minimum | Lower resolution causes fuzzy bars |
| Format | SVG or high-res PNG | SVG scales without quality loss |
| Colors | Black bars, white background | Maximum scanner compatibility |
| Size | 80-200% of nominal | Below 80% fails, above 200% wastes space |
| Quiet zone | 11× module width each side | Scanner needs clear start/end |
| Material | Matte preferred | Glossy reflects laser, causing misreads |
Test before bulk printing: Print one barcode, scan it with your phone camera or a scanner app. If it reads correctly, print the rest. This 30-second test saves hours of reprinting.
For Amazon Sellers: FNSKU vs UPC
If you sell on Amazon FBA, you deal with two types of barcodes:
- UPC/EAN: The product identifier you buy from GS1. You need this to create your Amazon listing.
- FNSKU: Amazon's internal barcode for FBA inventory. Amazon generates this — you print and stick it on your products before shipping to their warehouse.
You cannot use our generator for FNSKU — Amazon generates those in Seller Central. But you can use it to create UPC/EAN barcodes for your product packaging, GS1 applications, and non-Amazon retail channels.
Do you need a GS1 barcode?
Amazon now requires GS1-verified UPCs for most categories. The days of buying cheap UPC numbers from resellers are over — Amazon checks against the GS1 database. Budget about ₹22,000 ($250) for the initial GS1 registration for 10 barcodes.
How to Use the Tool (Step by Step)
- 1
Choose barcode format
EAN-13 for retail, Code 128 for internal use.
- 2
Enter your number
Type the product number — check digit auto-calculates.
- 3
Customize appearance
Adjust size, show/hide text below bars.
- 4
Download and print
PNG for digital, SVG for print. Test scan before bulk printing.
Frequently Asked Questions
How do I generate a barcode for free?+−
Open ToolsArena Barcode Generator, select your format (EAN-13, UPC, Code 128), enter your number, and download. Free, no signup, no watermark on the barcode.
Which barcode format do I need for my product?+−
For retail products sold in stores: EAN-13 (worldwide) or UPC-A (US/Canada). For shipping labels and logistics: Code 128. For internal warehouse tracking: Code 128 or Code 39. When in doubt, EAN-13 is the safest choice.
Do I need to buy a barcode number?+−
For retail products — yes, you need a GS1-registered number. For internal use (tracking your own inventory, library books, event badges), you can use any number you want. GS1 registration starts at about $250 for 10 numbers.
What is a check digit and do I need to calculate it?+−
The check digit is the last number in the barcode — it is a mathematical verification that the other digits are correct. Our tool calculates it automatically. Never type a random check digit manually.
Can I scan the barcode with my phone?+−
Yes — most modern phone cameras read barcodes natively. On iPhone, just open the camera and point at the barcode. On Android, Google Lens handles it. This is a great way to test your barcode before printing.
What is the difference between barcode and QR code?+−
A barcode stores a number (usually a product ID) in horizontal lines. A QR code stores text, URLs, or data in a 2D square pattern. Barcodes are for products and inventory. QR codes are for links, menus, payments, and anything that needs more than just a number.
Why is my barcode not scanning?+−
The three most common reasons: printed too small (below 80% nominal size), poor contrast (light bars on light background), or the quiet zone (blank space on sides) was cropped. Print at 300 DPI, use black on white, and never crop the edges.
Can I put my barcode on colored packaging?+−
Yes, but be careful with colors. The bars must be dark (black, dark blue, dark green) and the background must be light (white, light yellow). Avoid red bars — barcode scanners use red lasers and literally cannot see red ink.
Generate Barcodes — Free, Print-Ready
EAN-13, UPC, Code 128, Code 39. Download as PNG or SVG instantly.
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