The Thumbability criteria is measured on how easy the application is to use with only one hand, specifically one thumb.
- Thumbs up
The application can be comfortably used with one thumb. - It's a stretch
Tasks may be accomplished with one thumb but requires considerable effort and focus on the task. - Two Fingers Required
Many tasks may be thumbable, but two fingers are required to perform most tasks. Activities such as typing, or pinch zoom.