Describe the layout
Enter primary action position, navigation placement, assumed screen size, and hard-to-reach controls.
ONE-HANDED REACH CHECK
Thumb Zone
Analyzes mobile interfaces for one-handed usability and identifies important controls placed in difficult reach zones.
- Uses your inputs in a transparent calculation
- Instant result with practical next steps
- No signup required
Planning guidance only. Validate important decisions with customer evidence and your delivery team.
YOUR INPUTS
Build your result
Complete every field. The result updates only when you choose Calculate.
How it works
Get a reach score
Thumb Zone weighs each factor against known thumb-reach zones on large modern phones.
Reposition and re-check
Move key controls into the easy-reach bottom zone, then re-run the score.
Continue learning: Who should approve MVP requirements?
Frequently asked questions
Why does screen size matter for reach?
Larger phones push more of the screen out of comfortable one-handed thumb reach — the top corners in particular become effectively two-handed territory above about 6 inches.
Is a bottom tab bar always better than a hamburger menu?
For frequent, primary navigation, yes — it sits in the easiest reach zone. A side drawer can still work for secondary or infrequent actions.
Does this apply to tablets too?
This tool is calibrated for phone-sized screens held one-handed; tablets are typically used two-handed or resting on a surface, where reach zones work differently.
How We Compare
| Feature | MVPHub | Manual one-handed usability testing | Design heuristic checklists |
|---|---|---|---|
| Instant structured reach scoring | Included | Not included | Limited |
| Specific to one-handed thumb reach | Included | Limited | Not included |
| Real hand-size variation data | Not included | Included | Not included |
| Free | Included | Not included | Included |
Manual one-handed testing with real users and varied hand sizes remains the most reliable check. Thumb Zone gives a fast structural estimate before or alongside that testing.
Related tools
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