# Timing pattern

> The timing patterns are the alternating black-and-white lines running between the finder patterns, one horizontal and one vertical. They tell the decoder the module pitch, so it knows where each cell boundary falls.

Source: https://useqr.app/glossary/timing-pattern · Last reviewed 2026-08-21 · UseQR is free forever, MIT licensed, no signup.

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## What they do

After the finder patterns establish the corners, the decoder still needs to know the exact
grid spacing. The timing patterns are a run of alternating modules on row 6 and column 6,
functioning as a ruler.

They are why a code can be photographed slightly out of square and still be sampled
correctly: the decoder counts the alternations rather than assuming an even division.

## Design implications

Heavy styling that merges adjacent modules — very organic or "liquid" module shapes, or
aggressive rounding — damages the timing pattern first, because it depends on adjacent
modules being visually distinct. A style that keeps a visible gap between modules
preserves it.