QR Code Generator

How a QR code actually stores your data

A QR code is a two-dimensional barcode made of black and white squares called modules, arranged in a grid that can run from 21×21 up to 177×177 modules depending on how much data it holds. The encoder picks the smallest grid (called a "version", 1 through 40) that fits your text using one of four encoding modes — numeric, alphanumeric, byte, or Kanji — each packing data at a different density. A plain phone number encodes far more efficiently than a long URL with mixed-case letters and symbols, which is why very long links sometimes produce a noticeably denser-looking code. If what you need is the striped, one-dimensional kind that goes on a product or a shelf label, that is a different family of formats altogether — the barcode generator covers those, and they hold a number rather than a URL.

Where people actually put these

Beyond linking to a website, QR codes are commonly generated for Wi-Fi credentials so guests can join a network by scanning instead of typing a password, for vCard-style contact details on a business card, for a phone number pre-filled with a WhatsApp message, or for a fixed piece of text like a locker code or a serial number printed on equipment. Restaurants use them for digital menus, event organizers use them for entry tickets, and retailers stick them on packaging to link to setup guides or warranty registration.

• Wi-Fi network name and password
• A URL, phone number, or SMS template
• Plain text such as an address or reference code
• Contact details for a business card

Error correction: how much damage a code can survive

Every QR code includes redundant data calculated with Reed-Solomon error correction, so it can still be read even if part of it is smudged, torn, or covered by a logo. There are four levels — L (about 7% of the code can be lost), M (15%), Q (25%), and H (30%) — and higher levels make the grid denser because more of it is spent on redundancy rather than your actual data. Medium is a sensible default for most links; choose High if the code will be printed small, on fabric, or somewhere it's likely to get scratched or dirty.

PNG or SVG — which to download

PNG is a fixed-resolution raster image, ideal for dropping straight into a slide deck, a social post, or a web page at roughly the size you generated it. SVG is a vector format described in mathematical shapes rather than pixels, so it can be scaled up to a poster, a shop window sticker, or a billboard without ever looking blurry or pixelated — it's the better choice any time the code will be resized or sent to a print shop.

A quick tip before you print

Always leave a plain white margin (the "quiet zone") around the code and test-scan it on a real phone at the actual size it will be printed — a code that looks fine on a laptop screen can be too dense to scan reliably once shrunk down to a 2 cm sticker.