How to use the QR code generator
- Pick what the code should do: Text or URL, Wi-Fi, Email, Phone or Contact.
- Fill in the fields. For a link, paste the full address into Text or URL and start it with https://. For Wi-Fi, enter the Network name (SSID), the Password and the Security type.
- Leave Error correction on M for most jobs, or choose H for print that can scuff.
- Pick an Image size and the Foreground and Background colors, scan the preview with your phone, then download the PNG or SVG.
How the code is built
Your content becomes UTF-8 bytes plus repair data, and the generator picks the smallest QR version that fits. Version 1 is 21 x 21 modules and each version adds 4 per side, so the width is 17 + 4 x version. Digits-only and capital-letter-only text use denser modes. Reed-Solomon repair data comes in four levels that can restore about 7% (L), 15% (M), 25% (Q) or 30% (H) of the code, and higher levels make the code bigger, as Denso Wave explains. Every image has the four-module blank border (quiet zone) the standard requires, and the PNG uses whole pixels per module so edges stay sharp. Wi-Fi codes use the WIFI:T:WPA;S:name;P:password;; text that phone cameras recognize, with the characters \ ; , : " escaped.
Worked example
With the starting input https://example.com (19 bytes), error correction M and Medium size, the tool picks version 2, which is 25 x 25 modules. Adding the four-module border gives 33 x 33 modules, drawn at 8 pixels each, so the PNG is 264 x 264 px. At level H the same link needs version 3 (29 x 29 modules), because version 2 holds only 14 bytes at that level.
Limits and edge cases
- The biggest code (version 40, 177 x 177 modules) holds 7,089 digits, 4,296 capital letters and digits, or 2,953 bytes at level L, and less at M, Q and H. The tool tells you when content is too long.
- Long text makes small, dense modules. Shorten the link or print the code larger.
- Light-on-dark and low-contrast colors fail on some scanners, so the tool warns you.
- Emoji and non-Latin letters are stored as UTF-8. Phone cameras generally read them, but older scanner apps may show garbled characters.
- These static codes hold the content itself and never expire, but you cannot change where a printed code points or count scans.
Frequently asked questions
How much data can a QR code hold?
At most 7,089 digits, 4,296 letters and digits, or 2,953 bytes, in a version 40 code at error correction level L. Higher levels hold less. Short content gives a simpler code that scans faster and from further away.
Which error correction level should I choose?
Use M (about 15%) for most links and print. Pick Q or H if the code might be scratched or partly covered, and accept a denser code. Pick L for the simplest code on a screen.
Why does my QR code not scan?
Common causes are low contrast, a light foreground on a dark background, no blank border, a print size too small for the code density, and a blurry screenshot. This tool adds the border and warns about colors. Scan a test print with two phones.
Do QR codes expire?
Not these. A static code stores the content itself, so it works as long as it can be read. A dynamic code from a paid service points at a short link on their server and stops working if the service or your plan ends.
How do I make a Wi-Fi QR code?
Choose Wi-Fi, enter the network name exactly as it appears, the password and the security type (WPA for most routers), then download the code. A phone camera that scans it offers to join the network. Tick Hidden network only if your router does not broadcast its name.
Check a finished code with the QR code reader, make product labels with the barcode generator, or create a strong network key with the password generator.
Sources: Denso Wave, versions and capacity; Denso Wave, error correction; ZXing, Barcode Contents; RFC 2426, vCard 3.0.