QR Code Generator

How to make a QR code

1. Pick what the code should contain: a URL, plain text, Wi-Fi credentials, an email, a phone number, an SMS or a contact card.
2. Fill in the fields. The preview updates as you type, and the exact encoded string is shown next to it so you can check it.
3. Adjust the appearance — size, error correction level, colours and quiet zone — if the default black on white does not suit.
4. Download PNG for documents and screens, or SVG for print and anything that will be resized.
5. Scan your own code with a phone before you print a thousand of them.

How QR codes encode data

A QR code is a grid of black and white squares called modules. Three large finder patterns in the corners let a scanner locate and orient the code, alignment patterns correct for perspective, and timing patterns establish the grid spacing. Everything else is data plus error-correction codewords.

The interesting part is the format of the text inside. Scanners recognise a handful of prefixes and act on them:

Special characters matter. In a Wi-Fi payload the characters backslash, semicolon, comma, colon and double quote all have structural meaning, so a password containing any of them has to be escaped with a backslash. A vCard escapes semicolons, commas, backslashes and newlines instead. This tool handles both automatically, which is why a preview of the encoded string is worth a glance.

Error correction uses Reed–Solomon codes. Level L adds enough redundancy to recover about 7% of the code, M about 15%, Q about 25% and H about 30%. Higher levels mean more codewords, which means a denser grid for the same content.

Worked examples

Guest Wi-Fi card for a café. Network Cafe Guest, password flatwhite2024, WPA, not hidden. The encoded string is WIFI:T:WPA;S:Cafe Guest;P:flatwhite2024;;. Printed at 4 cm on a table card at error correction Q, it survives coffee rings and still scans.

A conference badge contact card. First name Ada, last name Lovelace, organisation Analytical Engines, phone and email filled in. The code carries a vCard of roughly 180 bytes, which fits comfortably and stays readable at 3 cm.

A campaign link in a magazine. A URL of 42 characters at level H produces a fairly sparse code that tolerates the rough registration of magazine printing. Download the SVG so the printer can scale it without softening the edges.

A colour experiment that fails. Foreground #1e90ff on white gives a contrast ratio of about 3.2:1. The tool warns, and in practice many older scanners will hesitate. Darkening the blue to roughly #0b3d91 pushes the ratio past 12:1 and scanning becomes instant.

Tips and common mistakes

• Keep the quiet zone. The blank border around a code is part of the specification — at least four modules, though two is usually enough on screen. Cropping it tightly is the single most common reason a code fails.
• Do not invert the colours. Scanners look for dark modules on a light background. A white-on-black code is technically valid but practically unreliable.
• Shorter content scans faster. A 40-character URL makes a much sparser, more forgiving code than a 300-character one. Use a short path rather than a long tracking URL.
• Test on both platforms. iOS and Android camera apps handle Wi-Fi and vCard payloads slightly differently. Two test scans cost nothing.
• Use SVG for print. A PNG scaled up in a layout program gets blurry edges, which reduces the contrast between modules.
• Do not put a huge logo in the middle. If you add one afterwards, use error correction H and keep the logo under about 20% of the area.

Privacy

Everything happens locally. The QR library runs in this browser tab, so Wi-Fi passwords, phone numbers, email addresses and contact details are never transmitted, stored or logged. The resulting image contains your data directly rather than a redirect through someone else’s server, which means nobody can count your scans, change the destination later, or take the code offline. That is also why it never expires.

Last reviewed: September 21, 2026