QR code generator

What this tool does

The QR code generator turns any short string of text into a QR code — a square matrix of black and white squares that can be read by a smartphone camera. The code is rendered in your browser as a PNG image you can download and use anywhere.

What you can put inside a QR code

Anything that fits in the byte limit (about 2,900 characters at the smallest error-correction level, fewer at higher levels). Common cases:

• A URL — the most common use. Print on a poster, business card, menu, or wall.
• Plain text — a Wi-Fi password, an email address, a short message.
• A vCard — formatted as BEGIN:VCARD\nN:Smith;John\nTEL:+15551234567\nEND:VCARD. Phones recognize this and offer to save the contact.
• Wi-Fi credentials — formatted as WIFI:T:WPA;S:NetworkName;P:Password;;. Phones connect automatically.
• A payment URI — Bitcoin, Lightning, SEPA, and other protocols all have URI schemes that work in QRs.

Error correction levels

QR codes have built-in redundancy so they can still be read when partially obscured, damaged, or photographed at an angle. There are four levels:

• L (Low) — about 7% of the code can be damaged and still readable. Smallest output for a given payload.
• M (Medium) — 15% damage tolerance. The most common default.
• Q (Quartile) — 25%. Use this when adding a logo over the center of the code.
• H (High) — 30%. Use for outdoor signage that might be partially worn or covered.

Higher error correction increases the size of the QR matrix for the same payload, but makes the code more robust. M is a sensible default for digital use; Q or H for anything printed.

Tips for reliable QRs

• Keep the URL short. Longer payloads make denser codes that are harder to scan.
• Leave a quiet zone (white border) around the code. The browser canvas above includes one automatically.
• Don't make the code too small in print. A rough rule of thumb is: scanning distance × 0.1 = minimum code side length. A code meant to be scanned from 1 metre away should be at least 10 cm on a side.
• Test before printing. Scan the QR with two or three different phones to make sure it works.
• Use dark on light. Some scanners can read inverted codes; many can't.

Privacy

The QR is generated in your browser. The text you encode never leaves your device. The QR-rendering library (QRious) is open source and is loaded once from a public CDN.