If you send emails, you want people to actually read them. Not just skim the subject line, but absorb the body text. One of the most overlooked details that determines whether your email gets read or deleted is the font's x-height. This small measurement makes a huge difference in legibility, especially on mobile screens where space is tight.

What exactly does 'x-height' mean in a font?

X-height is simply the height of a lowercase letter 'x' in a given typeface. It represents the main body of all lowercase letters (a, c, e, m, n, o, etc.). A font with a high x-height has taller lowercase letters relative to the uppercase letters and ascenders (like the stem of a 'd' or 'b').

Why do some fonts look bigger than others even at the same size?

This is the practical effect of different x-heights. Set two fonts at 14px. One looks small and cramped. The other looks open and easy to read. The one that looks bigger has a higher x-height. For email body text, this is critical. Most people read emails on their phones, often in poor lighting or while multitasking. A font with a high x-height improves readability by making the characters more distinct. You can read it faster and with less eye strain.

Which fonts have the best x-height for email body text?

Most web-safe fonts with good legibility have a relatively high x-height. Verdana was actually designed specifically for on-screen reading. It has a large x-height and wide spacing. Georgia is the serif equivalent, also designed for screens. Clean sans-serif fonts like modern clean sans-serif fonts often prioritize this feature because they are built for digital use. Other excellent choices include standard system fonts like Helvetica and Arial. If you are looking for free options for your campaigns, exploring free modern sans-serif fonts is a great start.

What are common mistakes people make with email fonts?

• Using display fonts for body text. Script or decorative fonts have varying x-heights and are almost impossible to read in long paragraphs.
• Ignoring mobile rendering. A font that looks okay on a desktop might be too thin or small on a phone.
• Forgetting about font fallbacks. If you specify a fancy font that isn't installed, the email client will use a default. Always specify a fallback like Arial or sans-serif.
• Setting the font size too small. Even with a high x-height, anything below 14px for body text is risky.

How do I test if a font has good x-height for my emails?

The simplest test is the squint test. Look at a paragraph of text in the font. If the lowercase letters look strong and clear, it likely has a good x-height. A more technical way is to compare the font against a standard like Arial. If the text looks noticeably smaller at the same pixel size, the x-height is probably lower. If you are designing from scratch, looking at a curated list of fonts optimized for email body text saves time. For the main content, stick to the legible workhorses. And if you need something for your sign-offs, check out these minimalist sans-serif fonts for signatures.

What is the first step to fixing my email font?

Check your email service provider's default body font. If it's Times New Roman or a generic serif, switch it. Pick a clean, modern sans-serif with a proven high x-height. Verdana, Arial, or a web font like Open Sans are safe bets. Set your body size to at least 14px. Send a test email to yourself and read it on your phone. That five-minute test will tell you everything you need to know. Get this one detail right, and your emails instantly become easier to read.

Learn More