Start with your body size

Whether you use a type scale or create your own size contrast, start with the size of the element that takes up the most space — the body copy. Body type design has the biggest influence on the legibility of the text and the overall appearance of the document.

While optimal text size depends on the typeface, avoid setting your body text size to less than 16px. This is the minimum size recommended by the Web Content Accessibility Guidelines for body copy. In the past, 12px was a more commonly used starting size, but it can be uncomfortable to read for long periods or on certain devices.

After establishing the body font size, decide how many hierarchy levels you need. As a general rule, a design should include 3: body text, subheading, and heading. From there, consider if extra levels like captions, pull quotes, meta information, or others are necessary.