In this guide
You cannot test every Android screen. You do not need to. Layout bugs cluster at the extremes: the smallest width you support, the widest, and the moments when the window changes size. Cover those and you catch most of what users would hit.
Pick a small set
Aim for four to five sizes, chosen by what can go wrong:
- Small phone. The narrowest, shortest screen you want to support. Finds clipped text, buttons pushed off screen and forms that need scrolling.
- Large phone. Finds stretched layouts and tap targets that sit out of thumb reach.
- Tablet. Finds a phone layout blown up to fill a wide screen: giant buttons, lonely columns of text, wasted space.
- Foldable, unfolded and folded. Finds layouts that break when the screen changes while the app is open.
- Any device in split-screen. A narrow window on a big screen behaves like a small device. See the split-screen checklist.
Your own analytics or the Play Console device data (if your app is live) tell you which sizes your users have. Without data, treat the list above as a starting point and say so in your notes.
What to check on each size
- Nothing is cut off. Titles, buttons, dialogs, the keyboard-covered input field.
- Everything is reachable. Scroll to the bottom of each screen. Can you tap the last button?
- Tap targets stay usable. Not tiny on a tablet, not overlapping on a small phone.
- Images keep their shape. No stretching, no blurry upscaling.
- Both orientations. Rotate on every size. See rotation and configuration changes.
- Text still reads well. Combine with the large font test.
Instructions you can give a tester
Testers without a device lab can still help. Ask them to send:
- Device model, Android version and screen size (Settings > About phone).
- A screenshot of the three most important screens.
- Whether anything was cut off, overlapped or hard to tap, and on which screen.
- Anything that looked different after rotating or changing the window size.
A short template keeps the answers comparable. Our bug report template works for this.
Turn findings into a fix
Group what testers report by cause, not by device. Three causes explain most cases: a fixed width or height in the layout, content that does not scroll when space runs short, and a phone layout stretched across a wide window. Fix the cause once, then re-test the smallest and the widest size. If a bug appears on only one device, note the model and settings before you decide it is rare; display size and font scale often explain it.
No devices? Use an emulator first
An emulator can model many sizes, including tablets and foldables. It will not show how a real screen feels in the hand, but it is quick for layout checks. See setting up an Android emulator.
Limits
Screen size is only one factor. Display size settings, font scale and window mode change the usable width too, so a single device can behave like several. Test those settings on at least one device.
More on device choice: which Android devices to test on.
Start free on AppReviewX and collect private, structured feedback from testers on different devices. Back to the overview: Android app testing.