accessibility
Target size
What is target size in accessibility?
Target size is how big a tappable or clickable control is, and how much space surrounds it. Too small or too crowded and people miss - fat fingers, tremors, small screens, a moving bus - and a control nobody can reliably hit is, for them, broken.
Also known as: touch target size, tap target
The demo
Tap the highlighted button each round. Try it with tiny, crowded targets, then with properly sized ones - and feel how much the margin for error matters.
Tap the highlighted button:
Hits: 0 · Misses: 0
Tap the highlighted target - mind your aim in tiny mode.
What this demo shows (text version)
A row of five adjacent buttons with one highlighted as the target to tap; the target moves each round. In "tiny" mode the buttons are small and packed tightly together, so it is easy to miss and hit a neighbour. In "adequate" mode they are around 44 pixels with comfortable spacing, and hitting the right one is effortless.
A tally counts hits and misses. The control and the task are identical; only the size and spacing change. The lesson is that target size and spacing decide how much margin for error people have - critical for touch, small screens, and anyone with reduced motor control. WCAG 2.2 sets a 24-pixel minimum, with 44-48 pixels recommended.
With the tiny targets you fumbled and hit the wrong one; size them up and the same task became effortless. Nothing changed but the box you had to land on. That margin for error - or the lack of it - is what target size buys, and it's invisible until it fails someone.
The numbers worth knowing: WCAG 2.2 sets a minimum of 24 by 24 CSS pixels (level AA), and the older AAA guidance and most mobile platforms recommend around 44 to 48. Spacing counts as much as size - small controls packed tight are worse than small controls with breathing room, because the danger is hitting the neighbour.
It isn't only for touch. Anyone with reduced motor control, a tremor, or a trackpad on a train benefits from a bigger target - this is [Fitts's law](/entries/fittss-law/) as an accessibility floor, not a nicety. Put generous size and spacing on anything people tap often, and never shrink a destructive action into a trap beside a safe one.