There are many details to check and refine to maximize the chances of your emailing campaign even before it is sent. Among these, today we will talk to you about the file sizes, their impact on loading times, and therefore on how recipients will react upon receiving your communication.
Determining the size of a file sent by email
The size of an email file is defined by the sum of all the elements that make up the email. Here are the main components that contribute to it:
1) The body of the text
Plain Text – Emails often include a plain text version for email clients that do not support HTML. Although plain text is generally lightweight, it nevertheless contributes to the total size.
HTML – HTML formatted emails may include tags, CSS styles, and sometimes JavaScript scripts. Complex and unoptimized HTML code can significantly increase the size of the email.
2) The images
Images embedded in emails, whether logos, banners, or product photos, contribute to the size of the emails.
Common image formats include JPEG, PNG, and GIF. Uncompressed or too numerous high-definition images can quickly weigh down an email.
3) The attachments
Attached files, such as PDF documents, PowerPoint presentations, Excel spreadsheets, or any other type of file, directly increase the size of the email. Large attachments can lengthen loading times and even be blocked by some email servers.
4) Scripts and tracking pixels
Some emails contain scripts or pixels (very small embedded images) for tracking openings and clicks. Although these elements are generally very small, their number and complexity can weigh down the total size.
5) Fonts and icons
Custom fonts and icon sets embedded directly in the email via CSS files or web fonts can also add to the total size of the email.
2 easy methods to measure the size of an email file
The first method is to use your email client. Most, such as Outlook, Gmail, or Thunderbird, for example, display the size of the emails in the user interface. The second method is fairly universal and involves downloading the email as a file to your computer, then checking the file size.
Why is email file size important?
Impact on user experience
The size of email files directly influences the user experience. In fact, overly large emails can take time to load, especially on slow or unstable internet connections. This can frustrate the recipient, who sometimes decides not to wait and move on. Some even go so far as to unsubscribe from the mailing list.
Compatibility and email filtering
Email service providers often have limits on the size of emails they can handle. An overly large message risks being rejected or filtered as spam, which greatly reduces your chances of reaching your target audience.
Additionally, some email clients cannot display heavy emails properly, which harms the presentation of your content. An undesirable factor, especially if you have spent time and effort working on that same content.
What email file size should be respected to avoid these inconveniences?
It is generally recommended to send emails as lightweight as possible while ensuring they contain all necessary information and are visually appealing. For standard and mobile supports, we advise keeping the total email size (including text, images, and other files) below 80 KB (e.g., Gmail truncates above 102 KB). This size ensures that the email loads quickly even on slow internet connections.
Regarding attachments, the size varies slightly depending on the email provider. For example, the maximum is 25 MB on Gmail and 20 MB on Outlook.
Strategies to optimize the size of files sent by email
Compress the images
Compressing the images is an effective method to reduce the size of your emails without compromising quality. Use image compression tools such as TinyPNG or JPEGmini to optimize your visuals before inserting them into your emails.
Use appropriate file formats
Choosing the right file format can also make a big difference. PNG and JPEG formats are generally preferable for images, while GIFs can be used for simple animations. Avoid using BMP or TIFF files, which are often larger.
Limit attachments
Attachments can significantly increase the size of your emails. Instead of attaching large files or too many attachments, consider including links to downloads hosted on your website or a cloud storage service in your message.
Optimize HTML code
Clean, well-structured HTML code can also contribute to reducing the size of your emails. Avoid unnecessary tags, redundant styles, and excessive scripts. Use tools like HTML Cleaner to optimize your code before sending.
Email file size and loading times are crucial factors for the effectiveness of your emailing campaigns. You now have all the tools in hand!
