Why your QR code stops scanning when you put a logo in the middle

Mr logo — Tue, 08 Sep 2026 16:00:56 +0000

The problem — a logo-in-the-middle QR that scans on your phone and fails on a customer's.
What error correction actually is. Levels L (7%), M (15%), Q (25%), H (30%): how much of the code can be destroyed before the data is unrecoverable.
Why a logo is "damage". The decoder doesn't know it's a logo. Cover 22% at level M and you are past the budget with nothing left for a scratch, a fold, or bad light.
The rule of thumb: keep the logo under 20% of the code's area, and use level H whenever you cover anything at all. Show the same payload at L and H side by side — H is visibly denser, and that density is the redundancy.
The three things that break a code faster than a logo: too little quiet zone, low contrast (light-on-dark, or a colour whose luminance is too close to the background), and printing it smaller than 2cm.
Link to your own /qr-logo page as the worked example, not as a pitch.

“I build FreeOnlineQR, a free QR and barcode generator — the logo tool above is part of it.”

DEV Community: Mr logo