It's a common issue to find that while the line heights of an email look perfect in the editor, once viewed in Microsoft Outlook the spacing is completely off.
Because different email clients render HTML in their own ways, display inconsistencies can happen. Outlook—specifically desktop versions like 2016, 2019, and earlier—is particularly notorious for line height and spacing issues.
This article explains why these line height issues occur in Outlook and provides actionable workarounds to help you fix them.
Inconsistencies between blocks?
If your main issue is inconsistent line spacing or formatting between different content blocks: follow the steps outlined here.
Why Does Outlook Display Line Heights Differently?
Unlike web browsers or modern email clients (like Gmail or Apple Mail), desktop versions of Outlook use Microsoft Word as their rendering engine. This means Outlook processes email code the same way it processes a printed document.
Because of this, standard web-based CSS properties for spacing, typography, and line height are often ignored, misinterpreted, or overridden by Outlook's default behaviors.
Common Outlook Line Height Issues and Workarounds
Here are the most common line height glitches you might encounter in Outlook, along with the best ways to resolve them.
1. Unresponsive or Exaggerated Line Heights
In Outlook 2016 and 2019 running on Windows, proportional line heights often don't render correctly. You might set your line height to 1.3 or 1.8, but Outlook will display them identically. In other cases, Outlook's rendering engine acts like a rubber band, stretching to fit the tallest element on a line and adding 20% to 30% more line height than you intended.
The Workaround: If your text looks too spaced out, try adjusting your paragraph spacing using the editor's block settings. For tighter text, remember that holding
[SHIFT + ENTER]creates a single line break, which behaves differently than a standard paragraph break created by hitting[ENTER].
2. Huge Gaps When Headlines Wrap
When a long headline drops down to a second line (wraps) in Outlook, a much larger vertical gap may appear between the two lines than what you see in the Envoke editor or in other email programs.
The Workaround: Isolate your headlines. Put headlines in their own separate content block so their line height can be controlled independently of your paragraph text.
3. The "Thin White Line" Bug
While not strictly a line height spacing issue, you might notice random, thin white horizontal lines cutting through your email layout or colored backgrounds in Outlook.
Why it happens: This is a known bug in Outlook's Word-based rendering engine that occurs during "pixel to point" conversion. When Outlook converts your font sizes or line heights from pixels (px) to points (pt) and ends up with a decimal value, it inserts the leftover decimal as an ugly white line.
The Workaround: Adjust your font sizes and line heights to be even numbers, and ideally divisible by four (e.g., 16px font with a 24px line height). While Microsoft has no plans to patch this in older versions, using multiples of four usually ensures a clean mathematical conversion and removes the white lines.
4. Extra Spacing in Outlook.com (Webmail)
Sometimes the issue isn't the desktop app, but the web version of Outlook. Outlook.com is known to automatically add extra spacing above and below headlines, or apply its own default line height (often 131%) to all text elements.
The Workaround: Ensure your content is clean of invisible code. When pasting text from Microsoft Word or Google Docs into Envoke, hidden formatting can carry over and clash with Outlook.com. Always use "Paste without formatting" (
Ctrl + Shift + Von Windows, orCommand + Shift + Von Mac) or use the "Reset Formatting" button in the Envoke toolbar to strip away interfering styles.
A Note on Outlook Market Share
While troubleshooting Outlook can be frustrating, it’s helpful to keep your audience in mind. Globally, less than 6% of email recipients use Outlook, and an even smaller percentage use the specific legacy versions prone to these exact display issues. (Note: A new version of Outlook scheduled for 2026 is expected to finally replace the Word rendering engine and put an end to many of these bugs).
Contacts viewing your emails on mobile devices, Gmail, Apple Mail, or newer email clients are not affected by these issues. You can always check the "opens by email client" breakdown on the main email reports page in your Envoke account to see exactly how many of your subscribers are using Outlook.
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