Change the numeric size
Google documents selecting text and using the toolbar’s Font size control. Its menu search also accepts font size followed by a number. Use a deliberate size for the selected passage rather than assuming the smallest-looking family is the same thing as the smallest point size.
Compare the same text fairly
Duplicate one short paragraph and keep its wording, margins and line spacing identical. Change only the family in one copy. This isolates differences in character widths and lowercase proportions instead of confusing them with different layout settings.
Choose scale for the reader
For a caption, begin with the viewing conditions and the amount of information it must carry. For a poster heading, start with the available space and the longest word. Shrinking every paragraph to fit a page can make the document harder to use even when the total page count improves.
Use document structure for consistency
Maintain a small hierarchy for headings, body text and notes. The Google Docs font guide explains font selection and styles. Keep a record of family and point size together so another editor can reproduce the intended hierarchy.
Your questions, answered.
Is the smallest-looking font always the lowest point size?
No. A family’s proportions and its selected point size are separate variables.
Is one font always the biggest?
The result depends on the chosen text, size and layout. Compare the actual passage rather than treating a family name as a universal size ranking.
Sources & background
Sources supporting this page’s explanations. Practical examples are our editorial suggestions.