Design
Dot-style QR codes — how far circles can go
Dot-style QR codes draw each module as a circle at about 84% of the cell width, keeping roughly 55% of the ink — enough for decoders that sample module centres, but the first style to fail as codes get denser or smaller. Keep the version low, the print generous, and the finder eyes solid.
The geometry of a dot
UseQR's style=dot replaces each dark module with a circle of
radius 0.42 × the cell — a diameter of 84% of the module width, which inks about
55% of the cell's area. That is well below a square's 100% and rounded's ~91%, and
it is the number every trade-off on this page flows from.
It still scans because decoders sample cells near their centres, and the centre of a dot is its most solid part. The visible white lattice between dots does not confuse the decoder — a majority-dark sample reads as dark. What the missing 45% of ink does cost is margin: blur, ink spread, glare and distance all push samples toward the background, and dots start that journey closer to the cliff edge than any common style except stars.
The density limit, in numbers
Dots fail when the circle itself approaches the resolution of the printer or the camera. The module count grows with the version, so density and physical size gang up:
| Code | Cells across (incl. quiet zone) | At 2 cm wide | Dot diameter | At 300 DPI |
|---|---|---|---|---|
| Version 3 (29 modules) | 37 | 0.54 mm module | 0.45 mm | ~5.4 px |
| Version 6 (41 modules) | 49 | 0.41 mm module | 0.34 mm | ~4.1 px |
| Version 10 (57 modules) | 65 | 0.31 mm module | 0.26 mm | ~3.1 px |
A 3-pixel circle at 300 DPI is barely a circle, and after ink gain on paper it may be barely a mark. Working rules:
- Keep the version low. Short URLs produce low versions; a long tracking URL can force version 10+ and quietly break a dot design that tested fine with placeholder data. This is the same mechanism as any too-dense code, amplified by 55% ink.
- Print generous. Dots at 4 cm behave like squares at 2 cm. Use the size calculator for the viewing distance, then add margin.
- Prefer SVG for print so the circles stay geometric instead of anti-aliased pixels.
Why the eyes stay solid
The three finder patterns are detected by their 1:1:3:1:1
dark-light ratio along scanlines, before error correction protects anything. Shattering
them into dots breaks that continuous ratio, so dot-style codes conventionally keep
solid eyes — UseQR defaults style=dot to eye=circle, a solid ring and ball that
match the round language without fragmenting. See
custom eye shapes for the variants and their risk
order. Try the combination:
a dot-style code with circle eyes.
Then verify at real size: the validator decodes the actual rendered artwork, which is the only way to know whether this payload, at this version, at this print size, keeps enough margin. Dot codes that pass at final size are dependable; dot codes assumed safe because a bigger test scanned are the classic "worked on screen, failed in print" story.
FAQ
Do dot-style QR codes actually scan?
Yes, reliably, when the code is low-density and printed at a generous size. Each dot keeps its cell's centre solidly dark, which is what decoders sample. The style fails when high version counts or small print shrink the dots toward printer and camera resolution.
Why do dotted QR codes keep square or solid corners?
The three corner patterns are how scanners find the code, using a continuous 1:1:3:1:1 dark-light ratio. Breaking them into dots fragments that ratio, so the eyes stay solid — usually as rings and circles that match the dot aesthetic.
What size should a dot QR code be printed?
Larger than the equivalent square code. As a rule of thumb, treat the usual minimums as starting points and add 50–100% — a close-range dot code is happier at 3–4 cm than at the 2 cm floor, and distance codes should follow the 10:1 rule with headroom.
Can I mix dots with a logo?
Yes, but the two draw on the same robustness budget. Dots reduce ink margin and a logo consumes error correction, so keep the logo small, use error correction H, and decode the finished artwork before committing to print.
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Related
- QR code design best practices — seven rules ranked — The seven design rules that decide whether a styled QR code scans, ranked by how often breaking them kills codes, with the number behind each rule.
- QR code module shapes compared — square to organic — Square, rounded, dot, diamond, star, bar and organic QR modules compared by ink coverage and scan risk, with the geometry numbers behind each style.
- Rounded vs square QR modules — when rounding costs you — Rounded modules keep about 91% of a square's ink and scan just as well, until small print sizes where corner radii shrink below printer resolution.
- Organic and fluid QR styles — controlled merging — Organic QR styles join neighbouring modules into flowing shapes. Why joining along the grid is safe, where blob styles go wrong, and how to verify.