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UX / UI High impact Easy 15–30 min
Font too small
Body text at least 16px, fine print at least 12px.
What it is
Font size determines readability. Text smaller than roughly 12px is hard to read on mobile and forces the user to zoom or squint.
Why it matters
Hard-to-read text increases fatigue and bounce rate and harms accessibility. Google reports "text too small" in the mobile usability test. Comfortable reading is the foundation of good UX.
How to do it
- 1Set the site's body text to 16px (1rem) or more.
- 2Keep fine print (captions, notes) at a minimum of 12px.
- 3Tune sizes relatively (rem) from the base size, not fixed in pixels.
- 4Test readability on a real phone, not just a large monitor.
Base font size
Correct
body { font-size: 16px; line-height: 1.6; }
.small { font-size: 0.875rem; } /* 14px */Conclusion
Readability is fundamental: 16px for body text is today's standard, and you shouldn't go below 12px. Work in rem from the base size so everything scales consistently. A cheap change with a big impact on reading comfort.
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