Minimum sensible button size on iPhone

Question

I\'m designing an iPhone app that features a rather large set of onscreen rounded rect buttons. Given finger-based touchscreen UI, what do you think would be the smallest se

Answer 1

In practice while creating a custom web-based device UI on early touch screens, we found it important to design for what one of our beta testers referred to as "my fat fingers." And he was right: it is easy to design elegant, fine controls that a significant number of users will find error prone or unusable. In that project, the exact size was application dependent, but that tester found 40 x 40 to be usable (double that for hi-def/Retina displays), anything less increased the number of misses and errors (and frustration); and as a bonus, people with slender fingers found it felt like they could move faster and didn't have to be as precise, which made the whole thing feel smoother, less subjective friction, more breathing room. The trick is to make controls of that size not seem clunky or overbearing; one solution is mentioned above, making the visual part of the control smaller than its actual dimensions, though that isn't a universal solution.