• Success Criterion 1.4.4
  • Conformance level AA

Mobile App That Ignores the Phone’s System Text-Size Setting

1.4.4 — Resize Text

Scenario

Setting

A fashion e-commerce site's checkout page

What’s wrong

A native mobile app ignores the operating system's text-size / display-zoom setting and offers no in-app way to enlarge text — users who need bigger text have no option at all.

Example 

// native app, hardcoded text size
Text("Total: $84.00")
  .font(.system(size: 14))
// ignores the OS Dynamic Type / font-scale setting entirely

Why it matters

A shopper who set a larger system font size for low vision still sees tiny, fixed-size checkout text with no way to enlarge it in-app.

How to test

On a native mobile app, change the OS text-size/display-zoom setting (Settings > Display > Font Size) and reopen the app: if text doesn't change size and there's no separate in-app text-size control, it fails.

How to fix

Build text with scalable APIs (Dynamic Type on iOS, sp units and font scale on Android) instead of a fixed point size.

// use the platform's scalable text style
Text("Total: $84.00")
  .font(.body) // respects Dynamic Type

Outcome

The shopper's larger system text size carries through to checkout, and they read the total without squinting.

Who is affected

Low-vision users on mobile apps, who rely on their phone's system text-size setting since most apps offer no separate zoom control.

Learn more

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