Website font should be easy to read at the usual distance from the user's eyes (20-30 cm for mobile phones). If your product is for people 35+, then the minimum text size should be 18px. Check this article about responsive website fonts:
The Responsive Website Font Size Guidelines
You're reading Font Sizes in UI Design: The Complete Guide. Quickly navigate to other chapters: Intro · iOS · Android · Web · Principles In this post, we'll cover what font size to use for a responsive website. First we'll cover mobile guidelines, then desktop guidelines. Ready?