QR code error correction (L, M, Q, H) explained

Four levels, one trade-off

QR standards define four correction levels: L, M, Q and H, with progressively more redundancy. Higher correction can help with limited damage, but leaves less capacity for the content and may produce a denser pattern.

The familiar percentage descriptions are approximate recovery capacity under specific conditions. They do not mean that the same percentage of any logo or scratch can always be covered.

When a logo is involved

Use the smallest logo that meets the design need, keep it centered, and select a suitable correction level. A logo can obscure critical patterns or too much data even when the code uses the highest level.

Run a decode test on the exported image. Then test a printed sample at its intended size and distance.

Choose for the job

For a clean, high-contrast code, the default medium level is a sensible starting point. Consider higher correction for a logo or likely wear, then check whether added density makes the code too small to print reliably.