When it comes to the button shape, rectangular buttons with slightly rounded corners are the safest choice — they ensure balance, symmetry, and trust. Rounded corners feel safer and more natural to users' eyes, while sharp edges may imply a threat.^[1]

Users are also quite familiar with circular buttons — for example, floating action buttons (FAB) that define the primary action on the page.

We don't want to undermine your creativity, but sticking to these shapes guarantees predictability, giving users a sense of control and comfort. Plus, it will prevent friction and unexpected product abandonment.

If you still decide to swim against the stream and try an unusual button shape, make sure to find ways to teach users so they can identify and recognize them as buttons.