Touch Target Size Checker
Check a button or link size against WCAG 2.5.8 (24px, with the spacing exception), WCAG 2.5.5 (44px) and the Apple and Android guidelines.
About this tool
Small targets are hard to hit for anyone with a tremor, limited dexterity or large fingers, and for everyone on a bumpy bus. WCAG 2.5.8 (Level AA, new in WCAG 2.2) asks for at least 24×24 CSS pixels, but a smaller target still passes if it has enough space around it: a 24px circle centred on it mustn't overlap the next target's, so a 20px icon needs a 4px gap. Links inside a sentence are exempt, as are targets whose size the browser sets.
WCAG 2.5.5 (Level AAA) asks for 44×44, the same as Apple's guideline, and Android's Material Design asks for 48×48dp. You can meet these without making icons look bigger by adding padding, which counts towards the target. The preview shows your target next to a neighbour at the gap you entered (sizes over 300px are shown at 300px).