QR Code Error Correction
The four error-correction levels explained, with guidance on when each makes sense and why logos need the highest.
What error correction does
QR codes use Reed–Solomon error correction to rebuild data that's damaged or obscured. The more correction you add, the more damage the code tolerates — but the more modules it needs, making the code denser.
The four levels
| Level | Recovery | Best for |
|---|---|---|
| L | ~7% | Clean digital display, maximum capacity |
| M | ~15% | General use (default) |
| Q | ~25% | Printing in busy or industrial settings |
| H | ~30% | Codes with a logo or likely wear |
Why logos need level H
Placing a logo over the center of a code destroys some modules. Level H can recover about 30% of the data, which is usually enough to keep a modestly sized centered logo readable. Always verify a logo code before printing.
The capacity trade-off
Higher correction means fewer modules are available for your actual content, so the code either holds less data or grows larger and denser. If your data is long, a lower level keeps the code scannable; if durability matters more, raise the level and accept a bigger code.
Choosing a level
Use M for most on-screen and clean-print uses, Q for signage exposed to wear, and H whenever you add a logo or expect scratches, folds or smudges.