ThisCalculator

Everyday

Change App Text Size on iPhone: Full Guide

Updated · Standard formula, shown below

Change App Text Size on iPhone: Full Guide

To change the text size inside individual apps on an iPhone, you use the per-app text size controls in Control Center or the app-specific settings in the app itself. This guide explains the built-in iOS methods, how to set a default text size, and how to override it for specific apps.

How iOS Text Size Works

iOS has two separate text size systems. The first is the system-wide text size, found in Settings > Display & Brightness > Text Size. This slider changes the font size for apps that support Dynamic Type, Apple’s system for adjustable text. The second is the per-app text size, which lets you override the system setting for a single app. This is useful when you want most apps at a comfortable size but need a larger or smaller size in one particular app, such as a reading app or a game.

Dynamic Type is supported by most Apple apps and many third-party apps, but not all. If an app doesn’t support Dynamic Type, changing the system or per-app text size won’t affect it. In that case, you may need to use the app’s own settings or the Zoom feature described below.

Setting a Default Text Size for All Apps

To change the text size for all apps that support Dynamic Type:

  1. Open Settings.
  2. Tap Display & Brightness.
  3. Tap Text Size.
  4. Drag the slider to the right to make text larger, or to the left to make it smaller.

The slider has 11 positions, from the smallest to the largest. The largest setting is about 135% of the default size. This setting applies to all apps that use Dynamic Type. It does not affect the size of text in apps that use fixed fonts, like many games or some utility apps.

Changing Text Size Only in One App

If you want a different text size in a specific app without changing the global setting, use the per-app override:

  1. Add the Text Size control to Control Center first (if you haven’t already): go to Settings > Control Center, then tap the green plus next to Text Size.
  2. Open the app you want to adjust.
  3. Swipe down from the top-right corner (on iPhones with Face ID) or swipe up from the bottom (on iPhones with a Home button) to open Control Center.
  4. Tap the Text Size icon (it looks like a small “a” next to a large “A”).
  5. Drag the slider up or down. The text in the app will change live.
  6. Tap anywhere outside the popup to close it. The setting is saved for that app only.

If you want to revert an app to the system default, repeat the steps and tap the Reset button at the bottom of the popup.

Using Bold Text for Better Readability

Sometimes increasing size isn’t enough; making the text bold can improve readability more than increasing the size. To enable bold text:

  1. Go to Settings > Display & Brightness.
  2. Toggle on Bold Text.
  3. Your iPhone will restart to apply the change.

Bold text works with Dynamic Type, so it will affect all apps that support it. It can make a big difference for users with mild visual impairments.

What If an App Doesn’t Change Size?

If you change the text size and nothing happens in a particular app, it likely doesn’t support Dynamic Type. This is common in games, some PDF readers, and older apps. In that case, you have a few options:

  • Look for a text size or font size setting inside the app itself. Many apps have their own display settings.
  • Use the Zoom feature: go to Settings > Accessibility > Zoom and turn it on. This magnifies the entire screen, not just text, and you can adjust the zoom level.
  • Use Display Zoom (on iPhones with a Home button): go to Settings > Display & Brightness > Display Zoom and choose “Larger Text”. This changes the resolution scale, making everything appear larger.

Comparing Text Size and Zoom

Text Size changes only the font size in apps that support Dynamic Type. It doesn’t affect images, buttons, or layout. Zoom, on the other hand, magnifies the entire screen, so everything becomes larger, but you may have to scroll more. Which one you choose depends on your needs:

  • Text Size: best for reading apps, email, and messaging, where you want more text on screen but at a larger size.
  • Zoom: best for apps that don’t support Dynamic Type, or when you need to see small details like icons or buttons.

Common Mistakes and Misconceptions

One common mistake is thinking that the system Text Size slider in Settings affects all apps. It only affects apps that use Dynamic Type. Another misconception is that per-app text size overrides are permanent; you can reset them anytime. Also, note that the per-app text size control in Control Center only appears if you’ve added it to Control Center; it’s not there by default on older iOS versions. Finally, if you have an iPhone with a Home button, the Control Center swipe is from the bottom edge, not the top-right corner.

Frequently Asked Questions

Why can’t I change text size in a specific app?

If the app doesn’t support Dynamic Type, the per-app text size setting will have no effect. Check if the app has its own font size setting in its preferences. If not, use the Zoom accessibility feature to magnify the screen.

Does changing text size affect all apps?

No, only apps that support Dynamic Type. Apple’s own apps and most modern third-party apps do, but some older or niche apps don’t. You can check by changing the size and seeing if the app’s text changes.

How do I reset per-app text size?

Open Control Center, tap the Text Size icon, and then tap “Reset” at the bottom of the popup. This will revert that app to the system default text size.

Can I set a different text size for each app?

Yes, you can set a different text size for each app that supports Dynamic Type. The per-app override is saved individually for each app.

What is the difference between Text Size and Display Zoom?

Text Size changes only the font size in Dynamic Type apps. Display Zoom changes the resolution of the screen, making all UI elements appear larger. Display Zoom is only available on iPhones with a Home button, not on Face ID models.

Will changing text size affect the size of icons on my home screen?

No, the home screen icons are not affected by Text Size. They are affected by Display Zoom (on supported models) or by the “Larger Text” option in Display Zoom settings.

Related

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.