What error correction actually does
QR codes use a form of the same Reed-Solomon error correction used in CDs, DVDs, and satellite transmissions: extra, redundant data gets woven into the code alongside your actual content, so a scanner can mathematically reconstruct missing or misread sections rather than needing every module to be perfect. The error correction level you choose sets how much of that redundancy gets included.
The five levels in this generator
| Level | What it does |
|---|---|
| Very Low | Smallest, simplest possible pattern for your content. Minimal built-in redundancy — best for screens and controlled printing, not for anything that might get damaged or covered. |
| Low | A modest step up in redundancy, still a compact pattern. Fine for clean digital use. |
| Normal | A solid default for most links and general use — reasonable redundancy without an oversized pattern. |
| High | Roughly 30% of the code can be damaged or obscured and still scan. The level to use for anything printed, handled, or logo'd. |
| Extreme | High-level redundancy plus a deliberately larger pattern for extra headroom — the most forgiving option, at the cost of the densest, largest code. |
The tradeoff: bigger isn't always better
More redundancy means more data has to be encoded, which means more modules, which means either a physically bigger code or smaller individual modules at the same print size. That matters because very small, tightly-packed modules can actually be harder for a cheap or older phone camera to resolve clearly at a distance — so "always pick the maximum" isn't automatically the right call for a plain link with no logo. Match the level to the situation instead of defaulting to the highest one.
Which level for which use case
- Plain link, digital only, no logo — Normal is plenty.
- Printed on a flyer or sign, no logo — High, for durability against wrinkles, glare, or partial obstruction.
- Any code with a logo overlay — High or Extreme, always. See How to Add a Logo to a QR Code.
- Small print size (business cards, product labels) — High, combined with a generous quiet zone in the Export tab.
- Codes that will be handled roughly (stickers, outdoor signage) — Extreme, to tolerate scratches, dirt, or fading over time.