QR code generator

Choosing an error-correction level

A QR code carries redundant data so it still scans when part of it is obscured. The four levels recover roughly 7%, 15%, 25% and 30% of the symbol — and the redundancy costs space, so a higher level means a denser code for the same content.

• L — on screen, undamaged, nothing on top of it.
• M — the sensible default for a web page or a slide.
• Q — print, or a small logo.
• H — anything printed small, anything laminated to a surface people touch, and anything with a logo in the middle.

Centre logos, honestly

A logo in the middle works because error correction reconstructs the modules it covers. It is a budget, not a free pass: the same budget is what absorbs a scuff, a fold, a bad print run and a poor camera angle. Spend all of it on the logo and the code scans perfectly on your monitor and fails on a printed flyer.

The slider is capped at what each level can genuinely spare. Print one and test it before printing a thousand.

Why the code gets smaller when you use capital letters

QR has a mode for the 45-character alphanumeric set that packs two characters into 11 bits instead of 16. HTTPS://EXAMPLE.COM qualifies and https://example.com does not. Schemes and hostnames are case-insensitive, so this tool uppercases them automatically — and leaves the path alone, because a path is not.

Keep the white border

The quiet zone — four modules of blank margin on every side — is part of the specification, not decoration. A code butted against a coloured background or a photo edge is the most common reason a technically valid symbol will not scan. Downloads here include it.

Nothing is uploaded

The encoder runs in this page. The SVG is generated here and the PNG is rendered from it on a canvas in your browser, so a code containing something private — a WiFi password, a single-use link — never reaches a server.