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QR Codes

What Is a QR Code?

A QR (Quick Response) code is a two-dimensional barcode made up of a grid of black and white squares, called modules. Unlike a traditional barcode, which only stores a short string of numbers in one dimension, a QR code stores data in both directions at once — which is why a single code can hold a full web address, an entire WiFi password, or a contact card instead of just a product number.

QR codes were invented in 1994 by Masahiro Hara, an engineer at the Japanese company Denso Wave, to track automotive parts through the manufacturing process faster than the barcodes of the time allowed. Denso Wave deliberately left the format open and royalty-free, which is a big part of why QR codes spread far beyond factories into menus, packaging, boarding passes, and payment systems worldwide.

How Do QR Codes Work?

Every QR code is built from a handful of standard structural pieces that a scanner looks for before it even tries to read the actual data. The diagram below highlights each one on a simplified example code.

Simplified anatomy of a QR code A diagram highlighting the finder patterns, timing pattern, alignment pattern, quiet zone, and data area of a typical QR code.
Finder patterns — the three bullseye squares in the corners let a scanner instantly recognize and orient the code, even if it's upside down or rotated.
Timing patterns — the alternating dashed lines connecting the finder patterns let the scanner count rows and columns accurately across the whole grid.
Alignment pattern — a smaller bullseye (larger codes have several) that helps the scanner correct for distortion on bigger codes or curved surfaces.
Quiet zone — the blank margin around the whole code. Without it, a scanner can't tell where the code begins and ends.
Data & error correction modules — everything else in the grid. These black-and-white squares encode your actual content, plus extra redundant data (added using Reed-Solomon error correction) that lets the code stay fully readable even if part of it is dirty, torn, or covered by a logo.

What Can a QR Code Store?

The grid size (called the "version," from 1 up to 40) determines how much data a code can hold — larger, denser grids store more information but require a bigger printed size to remain scannable. QR codes can encode a few different types of data:

Encoding Mode Stores Approx. Max Capacity*
Numeric Digits 0–9 only ~7,000 characters
Alphanumeric Digits, uppercase letters, and a few symbols ~4,300 characters
Byte Any text, URLs, or binary data (most common mode) ~2,950 characters
Kanji Japanese Kanji/Kana characters ~1,800 characters

*Maximum capacity at the largest QR version (40) with the lowest error correction level. Every tool on this page uses a much smaller, print-friendly version automatically based on your content — the tools below default to the "Byte" mode, which is what nearly all real-world links, text, and structured data (like WiFi credentials or contact cards) use.

Error Correction: Why QR Codes Still Scan When Damaged

QR codes use a form of math called Reed-Solomon error correction to add redundant data alongside your actual content. That's why a code can still scan perfectly even with a coffee stain, a scratch, or a logo placed in the middle — the scanner reconstructs the missing pieces from the redundant data instead of needing every module to be intact. There are four standard levels, each trading data capacity for damage tolerance: Low (~7% recoverable), Medium (~15%, the standard default), Quartile (~25%), and High (~30%, best for codes that will get dirty or include a logo). The QR Code Generator lets you choose the level directly, and the QR Code Logo Generator applies the High level automatically whenever you add a logo.

About These QR Code Tools

This collection of QR code generators and readers runs entirely in your browser — nothing you type, upload, or scan is ever sent to a server. Every generator below lets you preview your QR code before downloading it as a PNG at your chosen size or as a scalable SVG, so you always know exactly what you're getting before you print it on a flyer, menu, or business card.

Whether you need a quick QR code for a website link or something more specific — a WiFi network, a digital business card, a calendar invite, or a branded code with your logo in the center — there's a dedicated tool built for that exact format below.

QR Code Generator

The QR Code Generator is the fastest way to turn any link or block of text into a scannable QR code. Pick an error correction level, choose your download size, and export as PNG or SVG in seconds.

WiFi QR Code Generator

Stop reading your WiFi password out loud to every guest. The WiFi QR Code Generator builds a code that connects a phone to your network automatically the moment it's scanned with a camera app — no typing required.

QR Code with Logo Generator

Need something more polished than a plain black-and-white square? The QR Code Logo Generator embeds your logo in the center and lets you pick custom foreground and background colors while keeping the code fully scannable.

QR Code Reader

Already have a QR code as an image and just need to know what it says? The QR Code Reader decodes an uploaded or pasted image instantly, right in your browser.

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