How to use the QR code generator
The QR code (Quick Response code) was invented in 1994 by the Japanese company Denso Wave to track car parts, and it has become one of the most important entry points of the mobile internet. This tool generates codes entirely in your browser: the URL, WiFi password or contact details you enter never pass through any server. Press F12, open the Network panel and generate one — you'll see nothing is sent.
Choosing between the four content types
- URL: the most common. Scan it and the web page opens. Good for shop posters, product packaging, event materials.
- Plain text: scanning returns a string. Good for serial numbers, notices, device IDs.
- WiFi: scanning joins the network automatically, so nobody has to type a long password. Good for meeting rooms, cafés, guest houses.
- vCard: scanning saves a name, phone number and email straight into contacts. Good for trade shows and business cards.
Which error correction level?
QR codes carry built-in error correction, so they still read correctly even when part of the pattern is obscured. The four levels offer different tolerances:
- L (about 7%): the cleanest pattern and the smallest code for the same content. Good for on-screen display and high-quality printing.
- M (about 15%): the recommended default, plenty for everyday use.
- Q (about 25%): use it when printing onto material that wears, such as stickers or cardboard.
- H (about 30%): choose this when you plan to place a logo in the middle. The more of the centre is covered, the more correction you need as a safety margin. Note this tool doesn't add logos — overlay one yourself in an image editor.
Making a QR code easier to scan
Leave a white margin. A QR code needs a clear area at least four modules wide on every side (the "quiet zone"). Codes generated here include it. If you crop a code and paste it onto another image, don't trim that margin away.
Big enough and sharp enough. For print, at least 2×2 cm, and the pattern must stay crisp. On a poster, every extra metre of scanning distance needs roughly one extra centimetre of edge length.
Enough contrast. The foreground must be darker than the background, and more contrast is better. Inverted codes — light pattern on a dark background — are readable by some scanners, but not all, so for anything printed use a dark pattern on white.
Don't use red as the foreground. Some scanners convert the image to greyscale before decoding, and red turns into a low-luminance grey that blends into the background. Black, dark blue and dark green are all safe.
Frequently asked questions
Do generated codes expire? Is there a fee?
They never expire and it's completely free. That's because these are static codes — the content is encoded directly into the pattern with no server involved. Some commercial "dynamic code" services route you through an editable short link, and when that service shuts down the code dies with it. What this tool produces is static: the pattern itself carries the content, so as long as the image exists it will scan.
Why does a code with Chinese text look so much denser than one with English?
QR codes have dedicated compact modes for digits and for uppercase alphanumerics, where a character occupies very few bits. Chinese encoded as UTF-8 takes 3 bytes per character, and every byte has to be stored in full, so the same number of characters produces a visibly denser pattern at a higher version. That's a limitation of the format, not of the tool.
Should I download PNG or SVG?
PNG is a raster image that works anywhere — paste it into documents, slides, social platforms. SVG is a vector, so it scales to any size without blurring or jagged edges, which is what a print shop wants for large-format material. For everyday use, PNG is enough.
How much content can it hold?
It depends on the error correction level. This tool supports up to the maximum standard version (version 40): roughly 2,953 bytes at level L, 2,331 at M, 1,663 at Q and 1,273 at H. Remember that a Chinese character takes 3 bytes. If it reports the content is too long, lower the correction level or use a short link.
What if a WiFi code won't connect?
First check the encryption type. Almost every modern router is WPA/WPA2/WPA3, which corresponds to the "WPA" option; if the password box is left empty, the code means "join this open network". Older routers use WEP — pick "WEP". Also note that iPhones need iOS 11 or later, and some Android phones only recognise the code when you long-press in the camera app rather than scanning directly.
Is the content really not uploaded?
No, it isn't. The whole encoding algorithm (Reed-Solomon error correction, mask selection and so on) is JavaScript running inside the page; it computes locally and draws straight to a canvas. Try the tool with your network disconnected — it works exactly the same, which is the most direct proof there is.