Use an accessible starting point
Microsoft’s Outlook accessibility guidance recommends larger text, including 11 points or more in its web-email best-practices table, with familiar sans-serif families and sufficient space. Treat this as a stated starting recommendation rather than a guarantee for every recipient and display.
Keep the message structure simple
Use a brief heading only where it helps navigation, followed by ordinary paragraph text. Microsoft advises against excessive capitals, italics and underlining. Essential information should remain available as real message text rather than only inside a decorative image.
Separate reading controls from outgoing formatting
Keep signatures and links readable
Retain a clear difference between the main message and contact details without shrinking the latter excessively. Use descriptive link wording and a strong text-background contrast. The email-font collection offers family comparisons; size and layout still need to suit the actual message.
Your questions, answered.
Is one point size guaranteed to work for every email reader?
No. Client, display, zoom and recipient preferences can affect the reading experience.
Does a reading zoom change the authored font size?
Reading scale and composing typography have different scopes. Use the control for the intended task.
Sources & background
Sources supporting this page’s explanations. Practical examples are our editorial suggestions.