QR Code - LitekitHub

What is a QR Code?

A QR Code (Quick Response Code) is a two-dimensional matrix barcode invented by Denso Wave in 1994. Unlike traditional one-dimensional barcodes, QR codes can store information in both horizontal and vertical directions, offering higher data density and faster reading speeds. QR codes are now widely used worldwide in payments, product tracking, marketing campaigns, identity verification, and more.

How QR Codes Work

A QR code consists of a matrix pattern of black and white square modules (called "modules" or "pixels"). Each module represents a binary bit — black modules represent 1, white modules represent 0. This binary encoding allows QR codes to efficiently store numbers, letters, Chinese characters, and even binary data.

A complete QR code contains the following key components:

Finder Pattern: Three "回"-shaped square patterns in three corners of the QR code, helping scanning devices quickly locate and orient the image.
Alignment Pattern: Smaller "回"-shaped squares used for correcting image distortion, especially important in larger QR codes.
Timing Pattern: Alternating black and white lines that help determine module coordinate positions.
Format Information: Contains error correction level and mask pattern information, distributed around the finder patterns.
Data Area: The module area that actually stores user data.

QR Code Error Correction

QR codes have built-in Reed-Solomon error correction, allowing them to be correctly read even when partially damaged, obscured, or stained. QR codes support four error correction levels:

Error Correction Level	Recoverable Ratio	Use Case
L (Low)	~7%	Clean environments, e.g., product packaging
M (Medium)	~15%	General purpose, the most common choice
Q (Quartile)	~25%	Environments with possible light damage
H (High)	~30%	Harsh environments or with logo overlay

Higher error correction levels reduce the data storage capacity of the QR code. Our tool uses Level M by default, striking a good balance between storage capacity and error correction.

QR Code Data Capacity

The storage capacity of a QR code depends on the version (size) and error correction level. There are 40 versions of QR codes, ranging from 21×21 modules to 177×177 modules. Here are capacity references for common sizes (Error Level M):

Version	Modules	Numeric	Alphanumeric	Bytes	Kanji
1	21×21	27	17	11	5
2	25×25	48	29	20	10
10	57×57	414	251	172	106
40	177×177	7089	4296	2953	1817

Common QR Code Use Cases

Mobile Payments: The underlying technology for WeChat Pay, Alipay, and other scan-to-pay systems.
URL Sharing: Encode long URLs into QR codes so users can quickly access websites by scanning.
Wi-Fi Connection: Encode Wi-Fi SSID and password so scanning automatically connects to the network.
Digital Business Cards: Encode contact information (name, phone, email, etc.) for saving to address books with one scan.
Product Traceability: Print QR codes on product packaging so consumers can scan to view product origin and authenticity.
Event Check-in: Send QR codes containing unique identifiers for on-site check-in by scanning.
Identity Authentication: Used in two-factor authentication (2FA), such as QR code login.

QR Code vs 1D Barcode

Feature	1D Barcode	QR Code
Data Dimension	Single horizontal direction	Both horizontal and vertical
Data Capacity	~20 characters	Up to ~7000 digits or ~2900 bytes
Encodable Content	Numbers or simple letters only	Numbers, letters, kanji, binary data
Error Correction	None built-in	Built-in Reed-Solomon, up to 30% recovery
Reading Direction	Must align with scan line	360° omnidirectional reading
Typical Uses	Retail products, shipping labels	Mobile payments, URL sharing, e-tickets

How to Customize Your QR Code Look?

Our QR code generator allows you to customize the following key properties:

Size: Supports 128×128, 256×256, and 512×512 sizes to meet clarity requirements for different scenarios.
Foreground Color: The color of QR code modules, defaulting to black (#000000). You can choose any color to match your brand style.
Background Color: The background color of the QR code, defaulting to white (#ffffff). Dark backgrounds with light foregrounds create a reversed effect.

Generated QR codes can be downloaded directly as PNG image files for easy embedding in web pages, documents, or printing on physical materials.

Why Choose Our Online QR Code Generator?

Completely Free: No registration, no payment needed, unlimited usage.
Privacy Safe: All processing happens locally in your browser — your data is never uploaded to any server.
Live Preview: Instant QR code generation as you type, what you see is what you get.
Customizable Look: Freely adjust foreground color, background color, and output size.
One-Click Download: Download your QR code as a high-quality PNG image with a single click.
No Installation Required: Works in all modern browsers — just open and use.

Whether you're a developer needing quick test QR codes or a designer creating branded QR codes for marketing materials, our tool has you covered.

📱 二维码生成