QR Code Error Correction Explained (Levels L, M, Q, H)

What is QR code error correction?

QR codes have a remarkable feature: they keep scanning even when part of the code is dirty, damaged or covered. That's thanks to error correction — extra data (using Reed–Solomon coding) built into the code that lets a scanner reconstruct missing information.

The four levels

There are four error-correction levels, each recovering a different amount of the code:

• L (Low) — recovers up to ~7% of data. Smallest, densest code.
• M (Medium) — up to ~15%. A common default.
• Q (Quartile) — up to ~25%.
• H (High) — up to ~30%. Most robust, but holds less data at a given size.

The trade-off

Higher error correction means more resilience — but also more modules, so the code looks busier and needs to be printed larger to stay scannable. Lower levels give a cleaner, simpler code but less tolerance for damage.

Which level should you use?

• Clean digital use (websites, screens): L or M is fine.
• Print that may get scuffed (packaging, outdoor signage): Q or H.
• Adding a logo: use H — the higher correction lets the code tolerate a logo over the center. See how to add a logo safely.

Why logos work at all

When you drop a logo into the middle of a QR code, you're effectively "damaging" part of it. Error correction fills in the gap — which is exactly why branded QR codes with a center logo still scan, as long as the logo isn't too large.

Make a resilient QR code

Our generator builds codes with solid error correction so they scan reliably, logo and all. Create one now or browse all generators.