Should text be bigger on mobile?

Question

Should text be bigger on mobile despite the fact that we're dealing with smaller screen real-estate?

Pros:

• Easier to read while in motion
• Easier to read under difficult lighting

Cons:

• Requires more scrolling

Answer 1

Jakob Nielson and a large group of other studies suggest scrolling is not a con. Users are acclimated.

Put it into context. If you're sitting at a desk, the monitor is roughly 28 inches away vs. a mobile device that is 12 inches. Should it be larger if it's closer?

Four years ago, Smashing Mag found the most popular body font size on the web was 13px.

Now, most browsers default to 16px (1em/rem = 16px).

Other things to consider for readability.

1. Font: serifs v sans serif. Sans-serif fonts are generally easier to read if smaller and on display.
2. X-Height: higher is generally more readable (Georgia and Verdana).
3. Line-height: generally set to 1.5 (or 1.5 times font size)
4. Characters per line: In The Elements of Typographic Style, Robert Bringhurst suggests somewhere between 45 and 75 characters. However, on mobile, 35-50 is a good target.

These are basic guidelines that if you didn't loosely follow, would affect readability because user's rhythm, focus, and comprehension would be negatively affected.

Added source for 12-inch distance claim on mobile device

This article pretty much addresses the heart of your question and backs up many of my claims. Conclusion, smaller text on smaller screen because it's held closer.