Four levels, one tradeoff
QR uses Reed–Solomon error correction. The commonly quoted approximate recovery capacities are L 7%, M 15%, Q 25%, and H 30% of codewords, not a guarantee that the same percentage of visible area can be covered. Higher correction consumes capacity and can create a larger or denser symbol for identical content.
Logos are damage by design
A center logo overwrites encoded information. This tool switches to H when a logo is present and limits the logo area, but that does not guarantee a scan. Finder patterns, timing structures, contrast, and quiet zones still matter. Avoid logos with distracting borders or oversized white padding.
Choose correction for your use case
M is a useful general default for clean screens and printed handouts. Higher levels may be worthwhile for environments where a label can become dirty, but first improve the physical size and printing. Always test the exact exported design on multiple devices and at the final display distance.