qr-code-build

Design

Custom QR code generator

Colour, module shape and corner styling, with one constraint that never bends: a camera has to be able to tell dark from light.

  • Free
  • No sign-up
  • No expiry
  • Commercial use
Short answer

A custom QR code changes colour, module shape and corner styling while keeping the underlying pattern intact. Any design is safe as long as dark modules stay clearly darker than light ones, the three corner finder patterns stay recognisable, and the quiet zone stays empty.

Contents
Colour

Which combinations survive a camera

The decoder converts the image to greyscale before it does anything else. Hue is irrelevant; only luminance matters. Two colours that look completely different to you can be identical to the decoder.

ModulesBackgroundResult
Near-blackWhite or creamIdeal
Deep navy, forest, burgundyWhiteReliable — use these for brand colour
Mid-blueMid-greenFails — same luminance
RedBlackFails — no luminance separation
Yellow, pastel, neonWhiteFails — modules too light
WhiteBlack (inverted)Risky — many older scanners refuse

The quick test: screenshot the code, apply a greyscale filter, and look. If the pattern is hard for you to read, it is impossible for a decoder in poor light.

Shape

What rounding and dots really cost

Round modules and dot styles shrink the printed area of each dark module. That reduces the contrast the decoder sees at the boundary, and the effect compounds with small print sizes and cheap cameras.

  • Square modules — maximum reliability. The default for a reason.
  • Rounded modules — a small, safe softening. Fine at level M and above.
  • Dot modules — the most decorative and the least reliable. Use error correction Q or H, and print at least 25% larger than you otherwise would.
  • Styled corner eyes — safe, because scanners look for the ratio of dark to light bands through the finder, not for perfect squares. Round eyes preserve that ratio; eyes redrawn as logos or icons do not.
Rules

The four things that break any design

  1. Cropping the quiet zone. Four modules of clear space on every side. Designers cut this more often than anything else, and it kills the code outright.
  2. Inverting light and dark. The specification permits it; the installed base of scanners is less forgiving.
  3. Placing text or graphics over the modules. Error correction can recover a covered area, but only up to its level, and only if the damage is not over a finder pattern.
  4. Redrawing the finder patterns as brand shapes. Scanners find codes by these three squares. Change their proportions and the code becomes invisible to the scanner, no matter how clean the rest is.
Questions

Frequently asked

Can a QR code be any colour?
Any colour with enough luminance contrast. Dark modules on a light background is the rule; hue is free within that.
Do rounded or dot modules still scan?
Yes, with less margin. Raise error correction to Q or H and print larger than you would for square modules.
Can I change the corner squares to my logo?
No. Scanners locate codes by the finder patterns' band ratios. Changing their proportions makes the code undetectable.
How much of a code can I cover with a logo?
Roughly up to the error correction level, so about 30% at level H — but keep coverage central, under 25%, and never over a corner.
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Last reviewed 24 August 2026 · Checked by the QR Code Builder team