A QR code (Quick Response code) is a two-dimensional matrix barcode invented in 1994 by Denso Wave. It stores data in both horizontal and vertical patterns, allowing it to hold significantly more information than traditional 1D barcodes.

What are the different QR code versions?

QR codes range from Version 1 (21x21 modules) to Version 40 (177x177 modules). Each version increases capacity: Version 1 holds up to 25 alphanumeric characters while Version 40 can hold up to 4,296 alphanumeric characters or 7,089 numeric digits.

What is error correction in QR codes?

QR codes use Reed-Solomon error correction with four levels: L (7% recovery), M (15%), Q (25%), and H (30%). Higher levels allow scanning even when parts of the code are damaged or obscured, but reduce data capacity.

What data can a QR code store?

QR codes can store numeric digits, alphanumeric characters, byte/binary data, and Kanji characters. Maximum capacities range from 7,089 digits (numeric mode) to 2,953 bytes (binary mode) at the lowest error correction level.

/ /QR Code Generator

QR Code Generator

Generate a visual QR code pattern from text input. Select size and error correction level. This tool produces a visual representation of a QR code matrix.

Inputs

Text to Encode

0/200 chars

Size

Error Correction Level

Encoding Mode: Byte

Error Correction: M

Version: 1 (21x21 modules)

Results

QR Code (visual representation) — Version 1, 21x21

Input Text: (empty)

Character Count: 0

Encoding Mode: Byte

Error Correction: M

Data Capacity Used: 0/2,953 (Version 40 max)

Related Tools

References

Frequently Asked Questions

What is a QR code?: A QR code (Quick Response code) is a two-dimensional matrix barcode invented in 1994 by Denso Wave. It stores data in both horizontal and vertical patterns, allowing it to hold significantly more information than traditional 1D barcodes.
What are the different QR code versions?: QR codes range from Version 1 (21x21 modules) to Version 40 (177x177 modules). Each version increases capacity: Version 1 holds up to 25 alphanumeric characters while Version 40 can hold up to 4,296 alphanumeric characters or 7,089 numeric digits.
What is error correction in QR codes?: QR codes use Reed-Solomon error correction with four levels: L (7% recovery), M (15%), Q (25%), and H (30%). Higher levels allow scanning even when parts of the code are damaged or obscured, but reduce data capacity.
What data can a QR code store?: QR codes can store numeric digits, alphanumeric characters, byte/binary data, and Kanji characters. Maximum capacities range from 7,089 digits (numeric mode) to 2,953 bytes (binary mode) at the lowest error correction level.
How is data encoded in a QR code?: QR codes use four encoding modes: numeric (digits 0-9), alphanumeric (digits, letters A-Z, and symbols), byte/binary (ISO-8859-1 characters), and Kanji (Shift JIS characters). The encoder selects the most efficient mode based on input data.
What is the difference between QR codes and barcodes?: Traditional barcodes are 1D and store data in horizontal lines only. QR codes are 2D matrix codes that store data in both directions, allowing 10-100x more data capacity, faster scanning, and omnidirectional readability.
How do I scan a QR code?: Most modern smartphones can scan QR codes directly through the camera app. Point your camera at the code, tap the notification that appears, or use a dedicated QR scanner app. No additional software is usually required on iOS or Android devices.
Are QR codes secure?: QR codes themselves are just data containers and cannot execute code. However, they can encode malicious URLs leading to phishing sites. Always verify the destination URL before visiting, especially with codes from unknown sources.
Can I customize QR codes with colors and logos?: Yes, QR codes can be customized with colors, gradients, and logos while remaining scannable. The key is maintaining sufficient contrast and not interfering with the finder patterns in the three corners. Error correction level H provides the most flexibility for customization.
What is a static vs dynamic QR code?: Static QR codes encode data directly and cannot be changed after generation. Dynamic QR codes use a short URL that redirects to the actual content, allowing the destination to be updated without changing the printed code. Dynamic codes also provide scan analytics.
How many QR codes can exist?: The theoretical number of possible QR codes is nearly infinite due to the combinations of modules. Even at Version 40 with 177x177 modules, there are 2^(177*177) possible patterns, far exceeding any practical need.
What is the smallest size for a QR code?: A QR code should be at least 2 x 2 cm (0.8 x 0.8 inches) for reliable scanning on smartphones. The minimum size depends on the scanning distance: a general rule is that the code should be about 1/10th of the scanning distance.
Can QR codes expire?: Static QR codes printed on physical media never expire. Dynamic QR codes can expire if the redirect URL or hosting service is discontinued. Printed QR codes can become unscannable if the surface is damaged, faded, or obscured over time.
What encoding is used for QR code text?: QR codes in byte mode typically use ISO-8859-1 (Latin-1) encoding by default. For UTF-8 encoded text, the data must be encoded as bytes. Most modern QR scanners automatically detect and handle UTF-8 content when reading byte-mode QR codes.