QR Code With Logo

How the QR Code With Logo works

A plain QR code works, but a branded one gets more scans: people trust a code that visibly belongs to the business on the poster. The trick is that a logo covers part of the code, and the code has to survive that.

How a QR code with logo still scans

Every QR code carries Reed–Solomon error correction, the same family of codes used on CDs. At level High, up to 30% of the data codewords can be lost or wrong and the reader still recovers the message. This tool always encodes at High, then clears a box in the centre with a one-module margin and draws your logo inside it.

The logo covers a share of the code equal to the square of its width setting:

The centre of the code holds data and error correction blocks spread across the symbol, never the three finder squares in the corners or the timing lines, so a centred logo is the safest place to put it. Area grows faster than width, which is why the slider stops at 25%: beyond that a damaged or badly printed code has little margin left.

Colours and contrast

Scanners look for dark modules on a light background. The tool refuses a code colour that is lighter than the background, because many phones cannot read an inverted code. It also reports the contrast ratio and warns below 4:1.

Good pairs: navy, dark green, burgundy or charcoal on white or cream. Avoid mid greys, yellows and pastels for the code, and never use a busy photo as the background. If your brand colour is light, use it for the background and keep the code near black.

Choosing the logo file

• Shape: a square or round mark works best. A wide wordmark is scaled to fit the box and ends up very small; use the icon version of your logo instead.
• Transparency: a PNG with a transparent background sits on the cleared box in the background colour. A JPEG brings its own white or coloured rectangle.
• Detail: the logo will be printed small. Fine text inside it will not be readable.

If your logo has a solid background, the transparent PNG tool can remove it first.

Size for print

Each module must be big enough for a phone camera to resolve at the distance people will stand. A practical rule is a code width of at least one tenth of the scanning distance, and never under 2 cm. Short links make smaller codes with larger modules, so they print smaller and scan from further away.

The output is a square PNG from 1000 px by default. For print, 1000 px is enough for a code up to about 8 cm at 300 DPI; set 2000 or more for posters.

Tips and pitfalls

Test before you print. Scan the downloaded file with at least two phones, one older, from the real distance and in normal light. It costs nothing and saves a print run.

Keep the quiet zone. The white border four modules wide is part of the code. Do not crop it off or place the code on a busy design without it.

Keep links short. Every extra character adds modules and makes each one smaller. A short link on your own domain is better than a long tracking URL.

How to read the result

The stats give the QR version and grid size, the error correction level, the logo width, the colour contrast and the output size. A version under 6 with contrast over 7:1 is very robust.

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