This rule triggers when SiteGrasp detects that certain tap targets (e.g. buttons, links, or form fields) may be too small or too close together for a user to easily tap on a touchscreen.
Small or tightly packed links or buttons are more difficult for users to accurately press on a touchscreen than with a traditional mouse cursor. To prevent users from being frustrated by accidentally hitting the wrong ones, tap targets should be made sufficiently large and far from other tap targets that a user can press them without their finger pad overlapping any other tap targets. The average adult finger pad size is about 10mm wide (a bit less than half an inch), and the Android UI guidelines recommend a minimum tap target size of roughly 7mm, or 48 CSS pixels on a site with a properly-set mobile viewport.
You should ensure that the most important tap targets on your site—the ones users will be using the most often—are large enough to be easy to press, at least 48 CSS pixels tall/wide (assuming you have configured your viewport properly). Less frequently-used links can be smaller, but should still have spacing between them and other links, so that a 10mm finger pad would not accidentally press both links at once. Users should not have to pinch zoom (or rely on other browser UI features for disambiguating finger taps, such as Chrome's popup magnifying glass) in order to easily and reliably press the desired button or link.
Make important tap targets large enough to be easy to press
This applies to the tap targets your users will use the most, such as buttons for frequently-used actions, search bars and other important form fields, and primary navigational links. These tap targets should be at least 7mm (48 CSS pixels if you have configured your viewport properly), and should have additional spacing around them if they are any smaller than 7mm.
Ensure there is extra spacing between smaller tap targets
It is reasonable for infrequently-used links or buttons to be smaller than the recommended size of 7mm, but there should still be no other tap targets within 5mm (32 CSS pixels), both horizontally and vertically, so that a user's finger pressing on one tap target will not inadvertently touch another tap target.