Will exceeding email size limits and causing clipping affect overall email deliverability and sender reputation?

Summary

Exceeding email size limits and causing clipping can negatively impact email deliverability and sender reputation through multiple pathways. While some experts suggest that clipping's primary impact is on open tracking or display, the consensus is that large emails, particularly those with poor coding or excessive images, can increase spam scores, trigger filters, and reduce engagement. Ensuring emails stay within provider limits, simplifying designs, optimizing images, and avoiding large attachments are crucial strategies to mitigate these risks and maintain a healthy sender reputation.

Key findings

  • Direct Non-Delivery: Exceeding hard size limits (e.g., 25MB for Gmail, variable limits for Exchange Online) results in immediate non-delivery of the email.
  • Gmail Clipping Effects: Gmail clips emails over 102KB, affecting tracking, user experience, and potentially hiding the unsubscribe link, which can lead to spam complaints.
  • Spam Filter Trigger: Large email sizes, especially when combined with poor coding practices or excessive images, can trigger spam filters, negatively impacting deliverability.
  • Reduced Engagement: Large emails can load slowly, leading to lower engagement, more spam complaints, and a decline in sender reputation.
  • Reputation Degradation: Repeatedly sending large emails can gradually degrade sender reputation over time, affecting the deliverability of all emails from that sender.

Key considerations

  • Stay Within Limits: Adhere to the specific email size limits imposed by different email providers (e.g., Gmail, Exchange Online).
  • Optimize Images: Compress images and use appropriate file formats to minimize email size and improve loading times.
  • Simplify Design: Use simpler email designs, minimize the use of complex HTML code, and avoid unnecessary elements to reduce file size.
  • Coding Best Practices: Follow best practices for coding HTML emails to avoid triggering spam filters and ensure compatibility across different email clients.
  • Prioritize Unsubscribe Link: Ensure the unsubscribe link is easily visible and accessible, even if the email is clipped, to reduce spam complaints.
  • Test and Monitor: Test emails across different email clients and regularly monitor deliverability metrics and sender reputation to identify and address any issues.
  • Avoid Attachments: Avoid including large attachments in emails. Instead, use links to files hosted online.

What email marketers say
9Marketer opinions

Exceeding email size limits and causing clipping can negatively impact email deliverability and sender reputation. Several factors contribute to this, including increased spam reports if the unsubscribe link is clipped and harder to find, triggering spam filters due to large file sizes, and decreased engagement as large emails load slowly. Optimizing images and code, simplifying email designs, and avoiding large attachments are recommended to mitigate these risks.

Key opinions

  • Spam Reports: Clipped emails can lead to higher spam reports if the unsubscribe link is hidden, as recipients may find it easier to mark the email as spam than to find and click the unsubscribe link.
  • Spam Filters: Large email sizes can trigger spam filters, negatively impacting deliverability, even if there isn't a universally agreed-upon size limit.
  • Engagement: Large emails can load slowly, leading to lower engagement, more spam complaints, and ultimately, a decline in sender reputation.
  • Sender Reputation: Repeatedly sending large emails can degrade sender reputation over time, potentially affecting the deliverability of all emails from that sender.

Key considerations

  • Optimize Images: Compress images and use appropriate formats to reduce email size and improve loading times.
  • Simplify Design: Use simpler email designs and minimize the use of complex HTML code to reduce file size and improve compatibility across different email clients.
  • Avoid Attachments: Refrain from including large attachments in emails. Instead, use links to files hosted online.
  • Regular Monitoring: Continuously monitor email deliverability metrics and sender reputation to identify and address any issues related to email size or other factors.
  • Test Email Size: Test your email to see how large the final version of the email is so that you can see if it causes clipping.
Marketer view

Email marketer from Mailchimp Resource shares that large email sizes increase the likelihood of being marked as spam. Optimizing images and code can help reduce the size and improve deliverability.

August 2021 - Mailchimp Resource
Marketer view

Email marketer from HubSpot shares that large email sizes can negatively impact deliverability and sender reputation. They advise using smaller, optimized images and keeping the HTML code clean and minimal.

January 2024 - HubSpot
Marketer view

Email marketer from Sendinblue notes that optimizing email size and structure, avoiding large attachments, and using compressed images can greatly improve inbox placement rates and sender reputation.

July 2024 - Sendinblue
Marketer view

Email marketer from ActiveCampaign shares that complex email designs and large image sizes can affect deliverability. They recommend simplifying designs and compressing images.

October 2024 - ActiveCampaign
Marketer view

Email marketer from Reddit shares that consistently sending large emails can increase spam scores. They advise keeping emails lean and optimized for better deliverability.

December 2021 - Reddit
Marketer view

Email marketer from Email on Acid explains that exceeding size limits can indirectly affect deliverability. Large emails can load slowly, leading to lower engagement and potentially more spam complaints.

December 2022 - Email on Acid
Marketer view

Marketer from Email Geeks recommends avoiding exceeding the size limit, as spam filters could penalize it, and it may slowly degrade sender reputation over time.

June 2024 - Email Geeks
Marketer view

Marketer from Email Geeks suggests that clipping messages could lead to more spam reports if the unsubscribe link is below the fold.

February 2024 - Email Geeks
Marketer view

Email marketer from Neil Patel Blog shares that large emails can affect deliverability. He notes that while there isn't a universally agreed-upon size limit, exceeding certain thresholds can trigger spam filters and reduce engagement.

December 2021 - Neil Patel Blog

What the experts say
4Expert opinions

Experts offer differing perspectives on the impact of exceeding email size limits and causing clipping. Some argue that clipping primarily affects open tracking and display, without directly impacting sender reputation or other messages. However, others suggest that excessively large and poorly coded emails can contribute to higher spam scores, trigger filters, and negatively impact deliverability, potentially leading to unsubscribes and a degraded sender reputation.

Key opinions

  • Limited Direct Impact: Some experts believe that clipping mainly affects open tracking (if the tracking pixel is clipped) and message display, rather than directly influencing sender reputation or deliverability for other messages.
  • Display Issue: Larger messages, in and of themselves, may be more of a display issue than a direct driver of poor reputation. The content and coding practices are critical.
  • Indirect Spam Impact: Excessively large emails, particularly those with poor coding practices and excessive images, can contribute to higher spam scores and trigger spam filters, thus indirectly affecting deliverability.
  • Poor Coding Effect: Poorly coded emails and large file sizes can make it harder for recipients to download and view the message, potentially causing them to unsubscribe and degrade sender reputation over time.

Key considerations

  • Code Optimization: Ensure emails are well-coded to minimize file size and avoid triggering spam filters.
  • Image Optimization: Optimize images to reduce file size and improve loading times.
  • Content Review: Carefully review email content to avoid using elements that may trigger spam filters.
  • Monitor Engagement: Monitor engagement metrics, such as open rates and unsubscribe rates, to identify potential deliverability issues.
  • Consider Clipping Effects: Be mindful of how clipping may affect the placement of critical elements, such as the unsubscribe link.
Expert view

Expert from Spam Resource explains that while email size is not a primary factor, excessively large emails, especially with poor code or excessive images, can contribute to higher spam scores and trigger filters.

June 2021 - Spam Resource
Expert view

Expert from Word to the Wise shares that poorly coded emails and large file sizes can negatively impact deliverability by making it harder for recipients to download and view your message. This often causes them to unsubscribe which over time can degrade sender reputation.

March 2025 - Word to the Wise
Expert view

Expert from Email Geeks explains that clipping messages will likely only affect the reporting of opens if the open tracking pixel is below the fold but will not affect other messages or senders.

April 2023 - Email Geeks
Expert view

Expert from Email Geeks states larger messages are a display issue, not a reputation issue.

May 2021 - Email Geeks

What the documentation says
5Technical articles

Email providers enforce size limits, and exceeding these can prevent delivery. Gmail clips emails over 102KB, impacting tracking and user experience, but this clipping doesn't directly harm sender reputation. Limiting HTML complexity and optimizing images are crucial for reducing email size and improving deliverability.

Key findings

  • Gmail Limit: Gmail has a 25MB message size limit; exceeding it results in non-delivery.
  • Gmail Clipping: Gmail clips emails larger than 102KB, affecting tracking and user experience but not directly impacting sender reputation.
  • Exchange Online Limit: Exchange Online enforces message size limits that vary by subscription, preventing delivery if exceeded.
  • HTML Complexity: Keeping HTML email code simple reduces the risk of being flagged as spam.
  • Image Optimization: Optimizing images significantly reduces email size and improves deliverability.

Key considerations

  • Stay Within Limits: Ensure emails remain within the size limits specified by each email provider.
  • Optimize HTML: Keep HTML code as simple as possible to avoid triggering spam filters and improve compatibility.
  • Compress Images: Always compress and optimize images for email to reduce overall size.
  • Test Clipping: Check if your email gets clipped by Gmail and consider re-arranging the email or optimising it for a smaller size if so.
Technical article

Documentation from SparkPost emphasizes that optimizing images for email, including compressing them and using appropriate formats, can significantly reduce email size and improve deliverability.

December 2024 - SparkPost
Technical article

Documentation from Google Workspace Admin Help explains that Gmail has a message size limit of 25 MB. Exceeding this limit will prevent the email from being sent or received.

October 2022 - Google Workspace Admin Help
Technical article

Documentation from Microsoft Learn specifies that Exchange Online has a message size limit which, if exceeded, will result in non-delivery. The specific limit varies based on the subscription.

October 2023 - Microsoft Learn
Technical article

Documentation from MDN Web Docs advises keeping HTML email code simple to ensure compatibility and reduce the risk of being flagged as spam. This includes limiting the size and complexity of the HTML.

September 2021 - MDN Web Docs
Technical article

Documentation from Litmus explains that Gmail clips emails larger than 102KB. When an email is clipped, it can affect tracking and user experience, but does not directly impact sender reputation.

January 2024 - Litmus