Mobile & Touch
Thumb Zone
Primary actions should sit where the thumb naturally reaches on a phone held one-handed.
Where it comes from
It comes from Steven Hoober's extensive research into how people actually hold and touch their phones. Watching thousands of users, he mapped which parts of the screen the thumb can reach comfortably during one-handed use.
Why it matters for your website
Phones are held, not just looked at. Hoober's research on how people actually hold devices shows the centre and lower portion of the screen are the easiest, most accurate reaches for one-handed use, while the top corners are a stretch. Placing primary mobile actions outside the comfortable thumb zone makes them harder to hit and easier to ignore.
Phones are held, not just looked at, and the holding hand shapes what's easy to reach. Hoober's research shows the centre and lower portion of the screen are the easiest, most accurate reaches for one-handed use, while the top corners are an awkward stretch.
So placement is an accessibility-of-reach question, not just a visual one. A primary action stranded in a top corner is harder to hit and, because it's harder, easier to ignore — whereas the same action in the comfortable thumb zone is effortless to tap, which is exactly where the most important mobile actions belong.
Wrong vs right
A primary mobile action placed in a top corner, an awkward stretch for a one-handed user.
The primary action in the lower or central thumb zone, where it's easiest and most accurate to reach.
Important controls scattered into the hardest-to-reach corners of the screen.
Frequently-used actions placed in the comfortable reach of the thumb.
Treating mobile placement purely visually, ignoring how the holding hand limits reach.
Designing for the thumb's natural range, so key actions are effortless to tap one-handed.
Understanding Thumb Zone
The thumb zone is the area of a phone screen that's comfortably reachable by the thumb during one-handed use. It comes from Steven Hoober's research into how people actually hold their devices — watching thousands of users and mapping where the thumb can and can't easily go.
The findings are consistent: the centre and lower portion of the screen are the easiest and most accurate reaches for a one-handed user, while the top corners require an awkward stretch or a re-grip. Because most people use their phones one-handed much of the time, this map of comfortable reach has direct design consequences.
The practical lesson is about placement. A primary action stranded in a hard-to-reach top corner is both harder to hit and, because it's harder, easier to ignore — so the most important mobile actions belong in the comfortable thumb zone, where tapping them is effortless. It's the mobile-ergonomics partner to Fitts's Law and touch-target sizing.
How Kweri checks it
Thumb-zone placement is partly assessable and partly contextual. Kweri can reason about where key actions sit on a mobile layout — flagging, for instance, primary actions placed in the hard-to-reach top corners rather than the comfortable lower or central zone. What it can't fully know is how your specific users hold their devices or which actions matter most in a given flow, since reach comfort depends on grip and intent. So Kweri can surface primary mobile actions that appear to sit outside the comfortable thumb zone and prompt you to reconsider their placement, while the final call accounts for your real usage patterns.
FAQ
What is the thumb zone?
The thumb zone is the area of a phone screen comfortably reachable by the thumb during one-handed use. Steven Hoober's research mapped it: the centre and lower portion are the easiest reaches, while the top corners require an awkward stretch.
Why does the thumb zone matter?
Because most people use their phones one-handed, and the holding hand limits what's easy to reach. Primary actions placed outside the comfortable thumb zone are harder to hit and easier to ignore, so key actions belong where the thumb naturally falls.
Where should I place primary mobile actions?
In the comfortable thumb zone — the lower and central portions of the screen, easiest and most accurate to reach one-handed. Avoid stranding important actions in the top corners, which require an awkward stretch or a change of grip.
Whose research is the thumb zone based on?
Steven Hoober's, who studied how thousands of people actually hold and touch their phones. His work mapped the realistic reach of the thumb during one-handed use and is widely cited in mobile design.
How is the thumb zone related to Fitts's Law?
Fitts's Law says targets are easier to hit when they're larger and closer; the thumb zone adds the ergonomic reality of where 'closer' is on a hand-held phone. Together they argue for large, well-placed actions within easy thumb reach.
Related principles
Tap targets need to be big enough, and spaced enough, to hit reliably with a finger.
The time to hit a target depends on its size and distance — small, far targets are hard to reach.
Teach a product in context, a step at a time, rather than front-loading a tour nobody remembers.
Attribution & sources
Identified by Steven Hoober. Catalogued from Steven Hoober — research on how people hold mobile devices.
Based on Hoober's research into one-handed phone use; there's no single canonical web source.
See Thumb Zone on your own site
Run a free Kweri audit — a plain-English review of your site’s speed, accessibility, SEO and design, ranked by what to fix first. No login, no jargon.
Run a free audit →