Why font size is a performance issue, not a style choice
Text that is too small does not get read with effort — it gets skipped. On mobile, where a large share of campaigns is opened, small type turns your copy into decoration and leaves the recipient with one easy gesture: delete.
There is also a trust dimension. The classic unreadable legal block can look as if information were being hidden. Accessibility guidance — WCAG, and the European Accessibility Act in force since June 2025 — formalizes what user experience already demanded.
Readers don't squint at small text. They skip it.
Recommended font sizes for email
How to read a font-size check
5 best practices
- Use 16 px as the standard for body text — it is the comfortable minimum on mobile.
- Reserve 14 px for genuinely secondary content, never for the core message.
- Treat 12 px as a strict floor, not a target: legal mentions read better — and more honestly — at 14 px.
- Check the distribution: one readable headline does not compensate for paragraphs of small type.
- Test on real devices, desktop and mobile — a size that works at 27 inches can fail at 6.
Common mistakes
- Shrinking text to fit more content above the fold.
- Designing at desktop width without a responsive layout: many mobile clients then scale the whole email down, text included.
- Setting footers and legal blocks at 12 px or less out of habit, as if legal copy did not need to be read.
- Putting text inside images, where its size shrinks with the image and cannot be adjusted.
- Combining small size with light grey text: readability problems compound.
How Inbox Maestro checks it
Inbox Maestro analyzes every text block of your test email and shows how your content splits across size ranges — including the share that falls below accessibility thresholds, with the blocks concerned highlighted. The result appears in the Checkup section of your report, under Composition.
Frequently asked questions
What is the minimum font size for email?
16 px is the recommended standard for body text, and 14 px for secondary text, legal mentions included. 12 px is a strict floor, never a target: below it, text is widely considered too small to read comfortably.
Is small text in email an accessibility compliance issue?
It can be part of one. WCAG and the European Accessibility Act, in force since June 2025, set expectations for readable digital content, and commercial emails linked to covered services are increasingly reviewed against them. Readable text sizes are a basic building block.
Does font size really affect engagement?
Text that requires effort gets skipped, especially on mobile. Readable type broadens your effective audience: more recipients actually process the message and reach the CTA.
Should mobile and desktop use different font sizes?
The same email is read in both contexts, so size choices must hold on the smaller screen. Designing for mobile-first readability is the safer default.