QR codes, explained without the math degree
A QR code is a grid of black and white modules that encodes a string of data — most often a URL, but also plain text, WiFi credentials or a pre-filled email. The three big squares in the corners are finder patterns that let a scanner orient the code; the rest is your data, woven together with redundancy so the code still scans when scratched, dirty or partially covered.
That redundancy is the error correction level: L, M, Q or H. Level M restores the data even if 15% of the code is unreadable, and H survives up to 30% — which is exactly why people can stick a logo in the middle of a code and have it keep working. The tradeoff is capacity: more redundancy means less room for your actual content.
Open the free QR Code Generator — no signup, runs entirely in your browser.
How to use it
- Pick a content type — URL, Text, WiFi or Email — and fill in the fields.
- Watch the live preview update, then tune error correction, margin and colors.
- Keep an eye on the contrast guard: if it warns, scanners will struggle too.
- Download the code as SVG or PNG, or copy the SVG markup to your clipboard.
Why this one
- WiFi mode escapes special characters in network names and passwords correctly — the bug that breaks most online generators.
- Deterministic output: the same input always produces the same SVG, byte for byte.
- Real error-correction control (L/M/Q/H), so you can balance capacity against damage tolerance.
- Everything is generated locally in your browser — WiFi passwords never leave your device.
Frequently asked questions
Do QR codes expire?
No. A QR code is just data printed in a machine-readable grid — it works forever. What can break is the thing it points at: if the encoded URL goes offline, the code scans fine but leads nowhere. Encoding a link you control is the durable option.
Which error correction level should I pick?
M is the right default for most uses. Choose H if you plan to overlay a logo or the code will live somewhere it can get damaged; choose L only when you need to squeeze in as much data as possible and the code stays pristine.
Why won't my colored QR code scan?
Scanners need strong contrast between the dark and light modules. Dark-on-light works; light-on-dark (inverted) fails on many readers, and low-contrast color pairs are unreliable. This tool warns you when the ratio drops below 3:1 — stay above it.
Is it safe to share my WiFi password in a QR code?
The code is generated locally in your browser, so nothing is sent anywhere while you make it. But remember the printed result IS your password in scannable form — anyone who photographs it can join your network. Treat printed WiFi codes like a spare key.