Is there a size limit for my email?

Internet Service Providers (ISPs) like Gmail and Microsoft will usually clip large emails and download them slowly. Learn about email size and what's recommended.


Topics covered in this article:

Optimal email code and image size for email clients

Managing the size of your email

Finding the size of your email

 

 

Optimal email code and image size for email clients


When an email client receives your HTML email there's a two-step process for rendering that email. First, the HTML is downloaded and rendered. Second, the images in the email are downloaded. This is why you will typically see the email load in two phases: HTML first, images second. The total size of the HTML and images combined results in how fast the email will be processed by the email client and on your device (desktop or mobile).

 

Generally speaking, optimal email size is:

  • HTML code 125K or less.
  • Individual image sizes 40K.
  • If you have a large mobile audience, the smaller the total email size, the better.

 

In addition to helping your email load time, there are a few reasons why it is important to keep the total size of your email as low as possible.

 

Truncating

Many email clients (especially mobile) truncate the email, cutting it off halfway or 3/4's of the way through. You will see a “Download More” button in many cases.

 

Example of message clipping…

 

Deliverability

ISP’s may block or "hold" large HTML emails for further examination. Large emails can be a sign of spam or an email carrying a virus or malware.

 

Example of a bounce back message indicating email is too large…

"Exceeded maximum inbound message size"

 

Mobile load time

With mobile opens between 60-70% it is more important than ever that your emails are as light as possible. Large images will download slowly and could even crash the email application on a mobile device. The easiest way to see if this is an issue is by testing your email on a mobile device.

 

 

 

Managing the size of your email

The following tips will help you manage the size of your email, improve user experience and engagement, as well as inbox deliverability.

 

Create lighter emails using emails with fewer columns, concise text and more links off to your website for additional information. Use the correct image format (details below) and reduce the number and overall weight of images as much as possible.

 

When choosing your image formats, consider your options. The three most common formats are GIF, JPG, and PNG.

GIF

Great for small, low color images, as well as images that include text

Examples include logos and buttons, also animated images

JPG

Great for photos (especially ones with lots of color) and making smaller file sizes

Reduce 40% quality

Examples include hero images

PNG

Great for small images with transparency

Displays best on mobile

Examples include header images, logos, and images with text

 

 

 

Finding the size of your email

 

You can find the size of your email in most email clients. But there's also an easy way to do this in your browser.

 

How to find the total weight - code + images - of your email using a browser:

 

1. Load the 'view email as webpage' link from your email in Chrome.

2. Right-click on the email and select 'Inspect'.

3. Select the Network tab from the inspector tools.

4. Reload the email in the browser tab.

5. The total weight in KB will appear at the bottom of the Network information.

 

 

Email code size in Outlook

 

In Outlook, find your email size under File > Info. Open the email you wish to review by double clicking on it, this should open it in a separate window. Click File on the top left corner, and then click the Info section. You will see a section titled Properties on the right. The email code size will be listed under Properties. This is the size of your email code, excluding images.

 

 

 

 

 

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