How QR code is generated

How QR Codes Are Formed: A Beginner-Friendly Breakdown

QR codes are everywhere—from restaurant menus to product packaging and event tickets. But have you ever wondered how these little squares of black and white pixels actually work? Let’s take a look under the hood and explore how QR codes are formed, layer by layer.

What Is a QR Code?

A QR code (short for Quick Response code) is a type of two-dimensional barcode. Unlike traditional barcodes that store data in lines, QR codes use a grid of pixels—either black or white—to represent information. These tiny squares can encode links, text, contact information, and much more.

How QR Codes are encoded

QR codes come in different sizes, known as versions. They are formed by a 2D array of pixels which are one color to represent 0 and contrasting color (usually) black to represent 1. QR codes can range from Version 1 which is the smallest version - a 21x21 grid of pixels up to the other end of the spectrum, Version 40 -177x177 grid of pixels. Despite the size difference, all QR codes follow the same structural principles.

Spotting a QR Code: Positioning Squares

One of the easiest ways to identify a QR code is by looking for the three large squares in the corners. These positioning squares help scanners determine the orientation and alignment of the code. They’re always the same size and appear in the same location, no matter how big the QR code is.

In larger versions, you may also spot additional alignment patterns that help fine-tune the reading process. It is used to rescale the QR code when it is read from varying distances or from oblique angles.

Timing Patterns and Synchronization

Between the positioning squares, there’s a one-pixel-wide line of alternating black and white pixels. This is the timing strip, which helps the reader determine the size of the QR code grid as well as the timing of the bits along both axis

Error Correction and Formatting

The next to the timing strip on a QR code is the format strip on a QR code is used to denote the format of the data in the QR code, the first of this is the level of Error correction used in the QR code. Error Correction ensures that the QR code can still be scanned even if they’re partially damaged. This is made possible through error correction. There are four levels:

These correction levels are stored in the formatting pattern, along with information about a special design rule known as a mask.

What's a Mask and Why Does It Matter?

QR codes don’t like large blocks of identical pixels because they’re harder for scanners to read accurately. To solve this, a mask pattern is applied. The mask is used to break up large blocks of identical bits to make the pattern easier to read. The mask selectively inverts certain pixels to break up big chunks of same-color blocks. Different masks are tested, and the one that results in the most readable pattern is chosen.

Data Storage and Zigzag Reading

All the elements mentioned so far prepare the QR code’s structure—but what about the actual data?

The data inside the QR code always starts from the bottom-right corner and follows a zigzag pattern, weaving up two columns at a time, then back down the next two, moving from right to left. The first four bits of the data specify the kind of encoding the data is stored in—such as numeric, alphanumeric, byte (for regular text), or Japanese Kanji. This is followed by a byte (8 bits) that indicates the message length.

After this the remaining space is available to fill in the bits of the message we want to store. For example, lets say we wanted to store figurehowto.com we will convert it into 1 and 0 then the bits into our QR Code using our zigzag path. The rest of the message follows the same path, one byte at a time.

We can convert figurehowto.com into ones and zeros using byte encoding. Byte encoding uses ASCII. Every character is assigned a number from 1 to 256. In our case "f" equals "102" in ASCII an "i" is assigned "105". and so on and so forth. You can play with our Text to ASCII converter. Then we convert the ASCII decimal into binary form. "f" is assigned "102" converted to binary "01100110"

When the message ends, four zeros (white pixels) are added as an end-of-message indicator. If there’s unused space after that, it gets filled with error correction data—generated using an algorithm called Reed-Solomon, a powerful method also used in CDs and digital TV signals.

Final Touches: Masking and Quiet Zones

After placing the data, error correction, and formatting information, the chosen mask is applied. This adjusts the pixel arrangement to make it more scanner friendly.

One last detail: the quiet zone. The region around the QR code must be empty and of uniform color. This 4-pixel-wide white border around the QR code creates visual separation from any background noise and ensures accurate scanning.

And There You Have It

With all parts in place—positioning patterns, timing lines, format and version info, message data, error correction, masking, and the quiet zone—you now have a fully functional QR code. It’s a marvel of modern information design, capable of packing a surprising amount of data into a tiny space.

Next time you scan a QR code, you’ll know just how much thought goes into that little black-and-white square. Here is a link to our QR code generator so u don't have to make QR codes yourself