If messages, menus, or buttons are hard to read, start with the iPhone's Text Size setting. You can also turn on Bold Text, increase size further with Accessibility settings, or use Display Zoom when the whole interface feels too small. These controls have different effects, so try them in that order. To change backgrounds or the broader appearance of Messages, see how to change the text message display on iPhone.
Change the standard text size
- Open Settings.
- For iOS 26, tap Display & Brightness. On iOS 27, tap Appearance. Use Settings search for Text Size if your layout differs.
- Tap Text Size.
- Drag the slider to the right to make supported text larger.
- Open Messages or another app and check the result.
The slider changes text in apps that support Dynamic Type. It is not a guarantee that every website, image, or custom app control will grow. If the change is too large, move the slider back left. The setting affects more than text messages; it can change system and supported app text across the iPhone.
Use the Text Size Slider in iOS 17
On an iPhone running iOS 17, open Settings > Display & Brightness > Text Size and move the slider right to increase the size. Use the preview, then return to Messages or another app that supports Dynamic Type to check readability. Move the slider left again if text becomes too large. This changes supported system and app text, not the font encoded inside a picture or every custom website element. Use the larger Accessibility sizes below if the standard slider is insufficient; Display Zoom changes more of the interface and is a different control.
Make text even larger
Open Settings > Accessibility > Display & Text Size > Larger Text. Turn on Larger Accessibility Sizes, then move the slider. This offers sizes beyond the regular Text Size slider. Test a few apps afterward: at very large sizes, some screens need extra scrolling or may place controls differently. You can return here and reduce the size whenever needed. The same settings exist on a tablet, covered in how to make text bigger on an iPad.
Use Bold Text or Display Zoom
Turn on Bold Text in Accessibility > Display & Text Size if thicker letter strokes would help. Display Zoom enlarges more of the interface, including controls and icons on supported models, while Text Size targets text. Try Bold Text first if the characters have enough size but not enough weight; try Display Zoom if icons and controls are also difficult to see. For temporary on-screen magnification, use Zoom in Accessibility. Magnifier is for viewing physical objects through the camera. For every sizing option, including larger Home Screen icons, see how to make apps bigger on iPhone. For Display Zoom, open Display & Brightness on iOS 26 or Appearance on iOS 27, then choose Display Zoom > Larger Text > Done > Use Zoomed.
Change text size for one app
If the rest of the phone looks fine, you can use the Text Size control in Control Center in supported iOS versions. Add that control if necessary, open the app you want to adjust, open Control Center, and choose whether the size applies to that app alone or all apps. Return to the app to check the result. A website or app with its own font controls may still need its separate setting. In Safari, for example, you can change the zoom level of web pages.
Work out why a page still looks small
A website can use its own text styling, and text drawn inside a picture cannot be resized with iOS Text Size. In Safari, use the page's text-size or Page Zoom control for a specific website. If a document is a scan, pinch-to-zoom or use a suitable document viewer. If every app's controls are tiny, Display Zoom may help more than an app text setting. If only one app ignores changes, check that app's own appearance options and update it if the developer has fixed accessibility support.
Confirm readability without losing usable space
After changing a slider, read an actual message, Settings page, and webpage you commonly use. Check whether buttons remain visible and whether you can scroll to hidden controls. A maximum setting is not automatically the best setting. The useful size is one at which you can read comfortably and still finish tasks. You can return to the same slider to reverse the change at any time.
Will Bigger Text enlarge the keyboard? It mainly affects supported text. Display Zoom is the broader interface control if keyboard keys and icons are the problem.
Why did one app change but another did not? App support differs. A per-app Control Center choice also intentionally limits where the size change applies.
Does Bold Text change the font size? It changes the weight of text. It can improve legibility without taking as much extra space as a larger size.
Apple's display and text settings guide explains the text, bold, and zoom controls. For making a screen easier to reach with one hand, see how to use Reachability.
Make System Text Bold, Including the Older iOS 7 Route
For current supported versions, open Settings > Accessibility > Display & Text Size and turn on Bold Text. Open Settings or another supported app and check that the lettering is heavier. Turn the same switch off to restore the previous weight. Apple’s readability guide describes this accessibility control. It affects supported interface text, rather than applying bold formatting to words you send in an email.
On an iPhone 5 with iOS 7, open Settings > General > Accessibility > Bold Text. Turn it on, then tap Continue in the restart prompt. After the phone restarts, check a Settings page to confirm the heavier text. This older change requires that restart; newer layouts differ. To undo it, return to the old switch, turn it off and follow any restart confirmation. Keep text size and text weight separate: the larger-text settings above adjust size.
Turn On Bold Text on an iPhone 6 With iOS 9
On an iPhone 6 still using iOS 9.3, open Settings > Display & Brightness and turn Bold Text on. Tap Continue when the old interface asks to restart, then check Settings or another supported app after the restart for heavier lettering. To undo it, turn the same switch off and follow its restart prompt. This historical Display & Brightness route differs from the iOS 7 General > Accessibility route and the current Accessibility > Display & Text Size route described above. Bold changes text weight; it does not change the font size or make every website’s text bold.
Matthew Burleigh is the founder, head writer, and editor of Solve Your Tech, which he launched in 2012. He has written technology tutorials since 2008 and worked in IT since 2003, including small-business support, IT management, and consulting. He holds Bachelor’s and Master’s degrees in Computer Science from Arizona State University.
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