Free Online Barcode Generator

How to use the barcode generator

1. Type the text or number you want encoded — a SKU, serial number, ISBN, or product code.
2. Choose a barcode format that matches your use case — CODE128, EAN13, UPC, or CODE39.
3. Select Generate barcode to render it instantly in your browser.
4. Download the PNG for printing, or copy the raw value to paste elsewhere.

Quick format comparison

Common mistakes to avoid

• Adding spaces, hyphens, or letters inside an EAN13/UPC value — those two formats only accept plain digits.
• Typing a full 13-digit EAN13 or 12-digit UPC where you guessed the last digit — leave it off and let the tool calculate the correct check digit for you.
• Printing a barcode smaller than roughly 1 inch (2.5cm) wide and expecting it to scan reliably every time.
• Using CODE128 or CODE39 for an item that needs to scan at a real retail checkout — most point-of-sale systems expect EAN13 or UPC specifically.

CODE128 is a high-density linear barcode symbology that can encode all 128 ASCII characters — uppercase and lowercase letters, digits, and punctuation. It automatically switches between three internal character sets to keep the barcode as compact as possible, which is why it's the default choice for general-purpose tracking.

When to use CODE128

Reach for CODE128 whenever you need to encode alphanumeric data that doesn't fit a fixed-length retail standard — internal SKUs, shipping and logistics labels, asset tags, ID badges, and warehouse tracking codes.

Real-world CODE128 examples

EAN-13 (European Article Number, now managed globally by GS1) is a 13-digit numeric barcode standard used at retail checkouts worldwide. It's structured as a country/prefix code, manufacturer code, product code, and a final checksum digit that lets scanners verify the number was read correctly.

When to use EAN13

Use EAN13 for retail products sold in Europe, Asia, and most international markets outside the US and Canada. Many online marketplaces also require a valid EAN when listing physical products, and book ISBN-13 numbers use the same 13-digit format.

Real-world EAN13 examples

The Universal Product Code (UPC-A) is an 11–12 digit numeric barcode standard used primarily in the United States and Canada. It's structurally compatible with EAN13 — a UPC can be read by any EAN13-capable scanner — which makes it the de facto standard for North American retail.

When to use UPC

Use UPC for retail products sold in US and Canadian stores, grocery items, and marketplace listings on platforms like Amazon or Walmart that require a valid GTIN/UPC for physical product listings.

Real-world UPC examples

How the check digit is calculated

EAN13 and UPC barcodes end with a single check digit that lets a scanner confirm the rest of the code was read correctly. This tool calculates it automatically using the official GS1 formula, so you only ever need to type the digits that actually identify your product — 12 for EAN13, or 11 for UPC.

EAN13 (13th digit)

1. Starting from the left, multiply each of the first 12 digits by 1 or 3, alternating position by position (1st digit ×1, 2nd ×3, 3rd ×1, and so on).
2. Add all 12 results together.
3. Take that total modulo 10. If the result isn't already 0, subtract it from 10 — that's the check digit.

UPC (12th digit)

UPC uses the same idea with the multipliers reversed — 1st digit ×3, 2nd ×1, 3rd ×3, and so on across the first 11 digits — then the same "round up to the next multiple of 10" step to get the final digit.

Worked example: for the first 12 digits 890103082619, the EAN13 formula produces a check digit of 1 — giving the complete, valid code 8901030826191.

CODE39 is one of the oldest and simplest widely-supported barcode symbologies. It encodes uppercase letters, digits, and a handful of symbols using variable-width bars, and is readable by nearly every barcode scanner ever made — including older industrial hardware.

When to use CODE39

CODE39 is a strong fit for logistics, industrial and automotive parts labeling, warehouse asset tags, and healthcare or medicine batch labels — anywhere robustness and backward compatibility with older scanners matter more than data density.

Real-world CODE39 examples

QR Code vs Barcode

Barcodes and QR codes both encode data for a scanner to read, but they're built differently and suit different jobs. Here's how they compare at a glance.

Accuracy & limitations

This tool generates mathematically valid barcodes and checks EAN13/UPC values against the official GS1 checksum formula, so any barcode you download will accurately encode the value shown. A few things are worth knowing before you rely on one:

• Valid isn't the same as officially registered. A correct checksum only means the number is well-formed — it doesn't mean it's licensed to you. For real retail sale, EAN13/UPC prefixes must be assigned by GS1.
• Print size affects scannability. A barcode that looks perfectly clear on screen can fail to scan if printed too small or too low-resolution — keep it at least 1 inch (2.5cm) wide when printing.
• Format support varies by scanner. CODE128 and CODE39 are excellent for internal and industrial use, but most retail point-of-sale systems only accept EAN13 or UPC.
• Contrast and background matter. Print on a plain white or very light background — busy patterns, low contrast, or colored backgrounds reduce scan reliability.