Definition
Line height is the vertical space between lines of text. Email clients apply different defaults, so setting it explicitly prevents cramped or oversized text.
Unitless values around 1.4 to 1.6 read best for body copy.
Line height drives readability and behaves inconsistently across clients, so setting it explicitly is important. Unitless values around 1.4 to 1.6 read best for body copy. Testing on mobile where readers scan quickly matters.
Setting Line Height
Set line-height explicitly on text-heavy elements.
Use unitless or fixed values to avoid inheritance quirks.
Why It Matters
Line height drives readability and behaves inconsistently across clients. Understanding it prevents cramped or broken text.
Best Practices
- Set line-height explicitly on text-heavy elements.
- Use unitless or fixed values to avoid inheritance quirks.
- Test line spacing on mobile where readers scan quickly.
- Avoid fixed pixel heights that clip descenders.
- Keep it consistent across the email.
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Related Glossary Terms
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Accessible CTA (Email)
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Adaptive Design
Adaptive design in email uses predefined layouts that adjust to specific device or client widths, rather than fluidly resizing to every possible screen.
AI-Generated Content in Email
AI-generated content in email is copy, images, code or subject lines produced by artificial intelligence tools to speed up campaign production and testing.
Alt Text
Alt text is the written alternative to an image in an email, displayed when images are blocked, slow to load, or consumed by screen readers.
Autoplay Video in Email
Autoplay video in email refers to the limited ability to play video content automatically when an email is opened, using specific client-supported techniques.
Frequently Asked Questions
Clients seed different base line-heights per font. Line height drives readability and behaves inconsistently across clients, so setting it explicitly is important.
Unitless 1.4 to 1.6 typically reads best for body copy. Unitless values around 1.4 to 1.6 read best for body copy.
Yes, fixed pixel heights can clip descenders in some clients. Testing on mobile where readers scan quickly matters.
A ratio like 1.5 relative to font size. Line height drives readability and behaves inconsistently across clients, so setting it explicitly is important.
Yes, significantly. Unitless values around 1.4 to 1.6 read best for body copy.