Best PracticeMar 15, 20269 min read

Email Width Best Practices

James Cooper — Email developer from Manchester, UK. James analyzed viewport metrics from 50,000+ email opens to determine optimal width recommendations across devices and clients.

Get the width wrong and your email overflows, gets horizontal scrollbars, or looks tiny on desktop. Here's what actually works across all email clients. Email width is a key topic in our ultimate guide to HTML email testing.

The Recommended Email Width

The industry standard is 600px for the outer container. This has been the safe default for over a decade, and it still works well in 2026.

600px is the sweet spot

It fits in all desktop preview panes (including Outlook's narrow reading pane), scales well on mobile, and avoids horizontal scrolling on any client.

Some teams push to 640px or even 700px for widescreen designs. This can work for web-based clients, but risks overflow in Outlook's desktop reading pane.

Responsive Email Width

For responsive email templates, the common pattern is:

Desktop: 600px fixed-width table
Mobile: 100% width with max-width: 600px
Breakpoint: 480px for single-column stack

<table role="presentation" width="600" 
  style="max-width: 600px; width: 100%;">
  <tr>
    <td style="padding: 20px;">
      Your content here
    </td>
  </tr>
</table>

Important: Outlook has only partial support for max-width and may not honor it reliably. Always set the HTML width attribute alongside CSS for Outlook compatibility.

Width by Email Client

Client	Preview Pane Width	Recommended
Gmail (desktop)	~620px	600px
Outlook (desktop)	~500-660px	600px
Apple Mail	Variable	600px
iPhone	320-428px	100% + max-width
Android	360-412px	100% + max-width

Common Width Mistakes

To avoid these issues, follow the principles outlined in our HTML email best practices guide.

Using only max-width — Outlook ignores it, so your email becomes full-width
Setting width in CSS only — Some clients need the HTML width attribute
Images wider than 600px — They overflow the container in many clients
No mobile breakpoint — Email looks tiny on phones when forced to 600px

Test Your Email Width

Preview Across Devices

See how your email width looks on desktop, tablet, and mobile across 10+ email clients. Catch overflow issues instantly.

Test Width Free →