The short answer
Change Font size when words are difficult to read but controls are otherwise comfortable. Change Display size or Screen zoom when icons, buttons, and the whole interface are too small or large. Use Magnification for temporary zoom. Consider custom logical density only when the built-in range cannot serve a specific advanced need.
These controls overlap visually but operate at different layers. Choosing the right layer preserves app layouts and makes the result easier to reverse.
Match the symptom to the setting
| What you notice | Try first | Why |
|---|---|---|
| Text is too small | Font size | Scales text designed in sp without deliberately shrinking controls |
| Text, icons, and controls are all too small | Display size / Screen zoom | Changes the overall interface scale |
| You need to inspect one area temporarily | Magnification | Zooms the view without redefining app layout density |
| You need precise testing or more range | Logical density override | Powerful and flexible, with greater layout and recovery risk |
| The image looks soft or screenshots have unexpected dimensions | Screen resolution setting or size override | This is not primarily a font problem |
Font size follows text semantics
Android developers are expected to size text in scale-independent pixels, or sp. The user's Font size preference adjusts that text while leaving ordinary layout dimensions in dp. Apps with fixed-height containers or text incorrectly sized in dp can still clip; that is an app accessibility problem, not evidence that the system setting is wrong.
Android 14 introduced nonlinear font scaling up to 200 percent. Larger text still grows, but already-large text grows less aggressively than small body text. The goal is to improve readability while preserving hierarchy and reducing clipping.
Display size changes the whole coordinate system apps see
Display size—called Screen zoom by some manufacturers—adjusts logical density. Text, icons, buttons, spacing, and the amount of content that fits can all change. Apps are notified of the configuration change and may recreate or relayout their screens.
This is often the correct setting when touch targets and controls feel small, not just the words. It is also more likely than Font size to move an app between compact and larger-screen layouts.
Magnification is temporary and task-specific
Magnification enlarges the current screen or a selected region so a person can inspect content and navigate. It is useful when a single app ignores font preferences, when an image contains small labels, or when temporary detail matters more than fitting content.
Because it is a viewing aid rather than a density reconfiguration, it does not ask every app to relayout at a different logical width.
When custom density is reasonable
- Testing whether an app handles compact and expanded layouts correctly.
- Using a specialist display workflow after the built-in Display size range proves insufficient.
- Creating a carefully tested preset for a tablet, foldable, kiosk, or external-display setup.
- Restoring a known logical scale after an OEM update changed it unexpectedly.
Reset in the same layer you changed
- 1.If you moved Font size, return that slider or use Reset settings on the same screen.
- 2.If you moved Display size or Screen zoom, reset that control before touching custom density.
- 3.If a changer or shell route applied an override, use its restore-original action or the matching wm density reset path.
- 4.Reboot and verify the lock screen, Settings, keyboard, and important apps.
Questions, answered
Frequently asked questions
Does changing font size change Android DPI?+
No. Font size adjusts text scaling, normally through sp. Display size and custom density affect the broader dp-to-pixel mapping.
Why does one app ignore my font size?+
The app may use fixed text dimensions, render text into images, or constrain containers so enlarged text clips. Test another app and report the accessibility issue to that developer.
Is a lower DPI better?+
It is not inherently better. A lower logical density generally fits more interface content and makes controls smaller. Whether that is usable depends on eyesight, touch comfort, app layouts, and the device.
Sources and review notes
We favor platform documentation and original project material. Device-maker behavior can still differ, so manufacturer-specific claims are kept narrow.
- Change text and display settings
Android Accessibility Help — User-facing instructions for Font size, Display size, bold text, and reset controls.
- Text scaling
Android Accessibility Help — Explains sp-based text, flexible layout requirements, and testing enlarged text.
- Android 14 accessibility: nonlinear font scaling
Android Developers — Official details on nonlinear scaling up to 200 percent.
- Support different pixel densities
Android Developers — Defines dp, sp, density scaling, and the distinction between density-independent layouts and physical pixels.
- Android 7.0 behavior changes: Screen Zoom
Android Developers — Platform explanation of Display size and density configuration changes.