CSS property · 11 real installs 14 Oct 2026 · data last changed 10 Nov 2026
line-height in email clients
Works in 20 of 21. Partial in Outlook Classic.
Your reader in Outlook Classic may not see line-height the way you wrote it, even if it looks right where you tested it.
caniemail (MIT) via @emailens/engine 0.18.22
What to do instead in Outlook Classic
Always pair font-size with an explicit line-height. Prefer unitless values for inherited typography. For pixel-perfect spacer rows, combine an explicit line-height with a height attribute on the <td> to give Outlook a stable vertical baseline.
- Buggy.
emandpxunits behave weirdly. Usemso-line-height-rule:exactly.
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line-height on 11 real installs
One Emailens probe, screenshotted on each install on 14 October 2026, next to our live preview of the same client. Where line-height is supported you should see: lines 32px apart.
caniemail: line-height is partly supported in Outlook Classic.
- Outlook 2019 (Windows) · counted as Outlook Classic Real screenshot
- Outlook 2016 (Windows) · counted as Outlook Classic Real screenshot
- Outlook 2007 (Windows) · counted as Outlook Classic Real screenshot
Buggy. em and px units behave weirdly. Use mso-line-height-rule:exactly.
caniemail: line-height works in Outlook 365.
This Outlook.com install drops the <style> in the head, so only inline styles apply.
caniemail: line-height works in Apple Mail.
caniemail: line-height works in Apple Mail iOS.
caniemail: line-height works in Yahoo Mail.
Also captured, not counted as evidence (4)
- Outlook for Microsoft 365 · not mapped to an engine client yet Real screenshot
- Outlook 2019 for Mac (legacy app) · not counted as Outlook for Mac Real screenshot
This is the legacy Outlook for Mac app. The new Outlook for Mac, which the table describes, drops gradients, grid sizing functions, var() and more.
- Gmail (web) · not counted as Gmail Real screenshot
This Gmail install does not apply Gmail's sanitiser, so it shows more than real Gmail does.
- Windows Mail · not mapped to an engine client yet Real screenshot
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All 21 clients, problems first
| Client | Support |
|---|---|
| Outlook Classic | Partial See caveat 1 |
Works in 20: Gmail, Gmail Android, Gmail iOS and 17 more. Show all
| Client | Support |
|---|---|
| Gmail | Works |
| Gmail Android | Works |
| Gmail iOS | Works |
| Outlook 365 | Works |
| Outlook (New) | Works |
| Outlook iOS | Works |
| Outlook Android | Works |
| Outlook for Mac | Works |
| Apple Mail | Works |
| Apple Mail iOS | Works |
| Yahoo Mail | Works |
| Yahoo Mail Android | Works |
| Yahoo Mail iOS | Works |
| Samsung Mail | Works |
| Thunderbird | Works |
| HEY Mail | Works |
| Proton Mail | Works |
| AOL Mail | Works |
| Fastmail | Works |
| Superhuman | Works |
Caveats (1)
- 1. Outlook Classic: Buggy.
emandpxunits behave weirdly. Usemso-line-height-rule:exactly.
Caveats as recorded by caniemail (MIT), one entry per wording.
How line-height behaves
line-height controls the vertical rhythm of text and is one of the most legibility-critical CSS properties in email. Email clients tend to add their own baseline corrections, and Outlook Classic often shifts line-height calculations by 1-2 pixels relative to web browsers, which can cumulatively offset long blocks of body copy.
- Outlook Classic uses a different baseline algorithm and can shift text vertically by a pixel or two compared to web browsers.
- Some Android clients scale line-height with user accessibility text-size settings, breaking precise vertical rhythm.
- Setting line-height as a unitless number (e.g. 1.5) is more reliable than fixed px values, as it scales with the inherited font-size.
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