How font size is different in iPhone 6 / 6 Plus as compared to earlier iPhones (e.g. 5S)--given both the different screen size and DPI?

  1. Did the perceived* font sizes in system interfaces and built-in apps grow proportionally with screen size?

    [*] Perceived--i.e. as measured in milimeters/inches, not in pixels.

  2. What are Apple's guidelines for app developers in terms of font sizes for 6/6+ as compared to earlier iPhones? How strictly are they enforced via app moderation (or any other means)? Should all apps effectively demonstrate the same font size for similar UI elements, or they are allowed to decide on the size individually? Should DisplayZoom and Dynamic Type be strictly supported by every app developer?

The reason I'm asking is that with iPhone 4 I struggle with a small font in most of the apps I use--so curious whether it will change if I switch to iPhone 6/+.


3 Answers 3


Above all, text must be legible. If users can’t read the words in your app, it doesn’t matter how beautiful the typography is. When you adopt Dynamic Type in your app, you get:

  • Automatic adjustments to letter spacing and line height for every font size
  • The ability to specify different text styles for semantically distinct blocks of text, such as Body, Footnote, or Headline
  • Text that responds appropriately to changes the user makes to text-size settings (including accessibility text sizes)

Make sure all styles of a custom font are legible at different sizes. One way to do this is to emulate some of the ways iOS displays font styles at different text sizes. For example:

  • Text should never be smaller than 11 points, even when the user chooses the extra-small text size. For comparison, the body style uses a font size of 17 points at the large size, which is the default text-size setting.
  • In general, font size and leading values differ by one point per text-size setting. Exceptions to this are the two caption styles, which use the same font size, leading, and tracking at the extra-small, small, and medium settings.
  • At the smallest three text sizes, tracking values are relatively large; at the largest three text sizes, tracking values are relatively tight.
  • The headline and body styles use the same font size. To distinguish it from the body style, the headline style uses a heavier weight.
  • Text in a navigation controller uses the same font size that body style text uses for the large setting (specifically, 17 points).
  • Text always uses either regular or medium weight; it doesn’t use light or bold.

iOS Human Interface Guidelines: Color and Typography


The answer is Yes and No, depending on the app developers. I purchased iPhone 6 Plus for the hope that I can see bigger text. But apparently, not every user or developer thinks the same.

On my iPhone 6 Plus, I turned on the "Zoom" mode in "Display & Brightness" for my aging eyesight. What it does is to render the text bigger. It works very well in Apple's own apps. The fonts are large and crystal clear. But when it comes to third-party apps, it is a mixed bag. There are some apps that are optimized for 6/6+ that render fonts beautifully and in large-enough sizes. But there are a majority of others (alas) that claim to be 6/6+ optimized but effectively make the rendered font almost 50% smaller than before the update. For example, 1Password, Flipboard and Pocket rendered fonts much smaller after the update. I regretted the updates and have contacted the app developers. On the other hand, the iCab Mobile browser rendered fonts as it should, comparable to Apple's own apps.

Now when I see the app developers release any 6/6+ optimized updates, I always take it with a grain of salt. A lot of them just change the resolution settings, put in higher-resolution graphics and call it an optimization. What they don't realize is that many people who buy these larger iPhones are expecting to use the bigger screen real estate to see bigger fonts, and the app developers need to tweak the app layout and design to achieve that. Some of the third-party so-called "optimized" apps display a lot of white spaces in their app now that the screen is bigger and their app is still using small fonts. For me, that is just stupid. Why I am buying a premium phone with a gigantic screen just to stare at white spaces? The app developers need to utilize that space for some useful purposes. I know some people would argue that they want to see more content and they prefer small fonts, but for my eyesight, a bigger font is not just a preference, it is a requirement. At least I want my apps to give me the option to increase font sizes. Or at the very least, these apps need to honor the global font settings that I made on my iPhone.


Here is my own experience. For a context: I currently have iPhone 4 and iPad 2 (non-retina); I'm choosing between buying iPad Mini 3 and iPhone 6. I decided to choose iPad Mini; TLDR:

  • several apps I use are more feature-rich in iPad version compared to iPhone version; it will take a year or two to appear on iPhone 6x (if at all): OmniFocus, Mail, Calendar
  • most critical apps (OmniFocus and Mail) already support DynamicType and, partially, Larger Text--which means I have a comfortable-size fonts on iPad Mini
  • I spend 2-3 hours per day with a portable screen, so larger is screen size means more comfort for eyes.

Now to my questions:

  1. Font sizes difference between 6x and earlier iPhones:

    • iPhone 6 has two modes: Standard View vs Zoomed View:

      • in Standard View, font sizes on iPhone are equal to iPhone 5x; larger screen space fits more content
      • in Zoomed View, font sizes on iPhone 6 are larger than on iPhone 5x, proportionally to the larger screen size; larger space fits exactly the same amount of content
    • To make things larger, there is Dynamic Type and Larger Text accessibility system settings (which allows even larger fonts). Support for them is not ubiquitous:

      • Almost every system app support Dynamic Type (which is system-wide font size settings); about half of them also support Larger Text accessibility settings
      • for third-party apps, it all depends. Some support Dynamic Type only, others also support LargerText; yet others ignore system settings but have their own font size settings; yet others both ignore system settings and have no own font size settings. See "Apple enforcement of font sizes" below for details.
    • To compare Dynamic Type system settings between 6 and earlier iPhones:
      • at Standard View: largest font on earlier iPhone is visually equal to "one before largest" on iPhone 6; the smallest font on earlier iPhone is equal to smallest on iPhone 6
      • at Zoomed View: largest font on earlier iPhone is visually equal to "middle" setting on iPhone 6
  2. Apple enforcement of font sizes:
    • with very few exceptions, support "Display Zoom: Zoomed" affects all of the (non-fullscreen) apps, built-in and third-party
    • Standard View vs Zoomed view seems to work equally for all (non-fullscreen) apps
    • support of Dynamic Type / Larger Size system settings remains at app developer's discretion: many major apps still don't support Dynamic Type nor have built-in font size settings (Facebook, Skype, Things, all the Google apps I tried)
    • there's effectively no benchmarking or standard on similar UI elements between different apps: every app developer decides on his own what is large enough
    • with several exceptions, font size is nearly the same between different apps that support Dynamic Type / Larger Size system settings

Bottom line: both iPhone 6 and iPad Mini can solve the "small font on iPhone 4" problem, provided that you use apps supporting Dynamic Type. And for apps without Dynamic Type, the problem is generally still there--and app developers are to be addressed with this.

See also the list of iOS apps supporting Dynamic Type / having its own font size setings (and of those that do neither).

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