iPhone (iOS) · Display & Sound
Increase Text Size and Boldness System-Wide
Text Size and Bold Text controls scale font size and weight across the system and supporting apps, making text easier to read without reducing the amount of visible screen content the way zooming would.
How to open Text Size & Bold Text
- Open Settings → Accessibility → Display & Text Size
- Adjust the Text Size slider, or enable Larger Text for extended sizes
- Toggle Bold Text on
- Confirm the change (may prompt a brief Home Screen refresh)
- Open key apps to verify readability improvements
What you should know
- Dynamic Type slider adjusts text size across all apps that support it
- Larger Accessibility Sizes provides an extended range beyond the standard slider
- Bold Text increases font weight system-wide for improved contrast and legibility
- Works alongside Zoom and Display Zoom for additional visual scaling options
Why it matters
Text legibility is one of the most impactful accessibility adjustments available, benefiting not just users with low vision but anyone reading in bright sunlight, at a distance, or simply preferring larger text for comfort. Because Dynamic Type is a system-wide standard that well-built apps respect, changing it once improves readability consistently across Messages, Mail, Settings, and many third-party apps rather than requiring per-app adjustments. Bold Text adds a complementary contrast boost that particularly helps with thin, light-weight fonts common in modern app design.
Best practices
- Start with the standard Dynamic Type slider before moving into Larger Accessibility Sizes
- Enable Bold Text alongside larger sizes for maximum contrast and legibility
- Test key apps after changing sizes, since not all apps fully support Dynamic Type
- Combine with Display & Brightness zoom options if text size alone isn't sufficient
Common problems and fixes
- Text doesn't get larger in a specific app
- That app may not support Dynamic Type; check for the app's own internal text size setting
- Layouts look broken after increasing text size
- Some apps handle very large accessibility sizes poorly; try a smaller increase or report it to the developer
- Bold Text requires a restart to fully apply
- This is expected—iOS may prompt a Home Screen refresh after toggling Bold Text
Tips and tricks
- Use Larger Accessibility Sizes for a substantial jump in readability beyond the standard range
- Pair with Increase Contrast under Accessibility > Display & Text Size for further legibility gains
Frequently asked questions
Is this the same as zooming the whole screen?
No, Text Size scales font specifically, while Zoom magnifies the entire screen including images and icons.
Does Bold Text affect icon labels?
Yes, it also thickens Home Screen icon labels and other system text for consistency.
Can text size be set differently per app?
No, the system-wide setting applies everywhere apps support it; individual apps may offer separate internal overrides.
Related settings
- Display & BrightnessDisplay & Brightness settings control screen brightness, True Tone, Dark Mode, text size, and Night Shift for warmer colors in the evening.
- Accessibility SettingsAccessibility settings on iPhone include VoiceOver screen reading, Zoom magnification, Voice Control, and many vision, hearing, mobility, and cognitive features.
- Captions & SubtitlesCaptions & Subtitles controls whether closed captions appear by default during video playback and lets you customize their font, size, color, opacity, and background style.
More Display & Sound guides for iPhone (iOS)
- NotificationsNotification settings let you control exactly how each app alerts you — as a banner, a sound, a badge, or grouped into a scheduled summary — so your Lock Screen and Notification Center reflect what actually deserves your attention.
- Sounds & HapticsSounds & Haptics controls ringtone and alert tones, ringer and alert volume, and the tactile vibration feedback (haptics) your iPhone provides for calls, texts, and everyday interactions like typing.
- FocusFocus lets you silence distracting notifications based on what you're doing — like Work, Sleep, or Personal time — while still allowing calls and alerts from specific people or apps you choose to come through.
- True ToneTrue Tone uses ambient light sensors to automatically adjust the display's white balance and intensity to match surrounding lighting conditions, keeping colors looking natural under different light sources.
- Night ShiftNight Shift automatically shifts the iPhone display to warmer colors on a schedule or from sunset to sunrise, reducing blue light exposure that can interfere with sleep when using the device at night.
- Dark ModeDark Mode changes the system interface and supported apps to a dark color scheme, and can be set to switch automatically at sunset and sunrise or on a custom schedule.