The four levels
QR codes support four error-correction levels, each able to recover a percentage of the code if it is damaged:
- L (Low) — recovers ~7%. Smallest, least dense code.
- M (Medium) — recovers ~15%. The usual default and a good all-rounder.
- Q (Quartile) — recovers ~25%. Good for slightly rough conditions.
- H (High) — recovers ~30%. Best for logos or harsh environments.
The trade-off
Higher error correction adds redundancy, which makes the code denser (more modules) for the same data. A denser code needs to be printed a little larger to stay scannable. So do not just pick H "to be safe" — match the level to the risk.
Which level should you choose?
- M for most everyday codes — links, Wi-Fi, posters in clean conditions.
- Q or H for codes exposed to wear: outdoor signage, packaging that gets handled, industrial settings.
- H whenever you place a logo in the centre — the logo covers modules, so you need the extra recovery. Our logo QR generator switches to H automatically.