What is Gmail clipping?
When an email's HTML file size exceeds approximately 102KB, Gmail hides the rest of the message behind a "View entire message" link. This is called clipping.
Clipped emails have lower effective engagement. Recipients who don't click the link never see your footer, unsubscribe link, or any content below the clip point.
Why 102KB?
Gmail doesn't publish an official number, but community testing consistently places the threshold at approximately 102,400 bytes (100KB). Some senders report the limit varies slightly, so treating 85KB as a safe ceiling and 102KB as the hard warning is reasonable.
What counts toward the limit?
The file size limit applies to the HTML source of the email. This includes:
- All HTML markup
- Inline CSS (style attributes on every element)
- Content: text, URLs, merge tags
- Comments
It does not include:
- Images (loaded externally)
- Fonts (loaded from Google Fonts or similar)
- Attachments
What causes emails to get large?
1. Inline CSS duplication
Email HTML requires inline styles on every element. A single email with 40+ elements repeating the same font-family: Arial, Helvetica, sans-serif across hundreds of occurrences adds up fast.
2. Long URLs
Tracking parameters make URLs longer. A URL like:
https://your-domain.com/product?utm_source=email&utm_medium=campaign&utm_campaign=spring-sale-2024&utm_content=hero-cta
is 117 characters. Multiply by 10 CTAs and that's already 1.1KB from links alone.
3. Preheader padding characters
A common technique uses zero-width characters or repeated spaces to push inbox preview text. This adds a few hundred bytes but should not be the primary cause.
4. ESP merge tags and conditionals
Complex conditional content and many merge tags increase source size before personalization is applied.
5. Minification not applied
Many ESPs send email HTML as-is, including whitespace, indentation, and comments.
How to check
Use the Gmail Size Checker tool in EmailingSimply. Paste your HTML and it shows the byte count and whether you're under the safe threshold.
You can also check locally:
wc -c your-email.html
How to reduce email size
Remove HTML comments
<!-- Remove all comments like this before sending -->
Shorten URLs at the ESP level
Let your ESP handle tracking parameter injection rather than embedding full URLs in the source. Some ESPs (Klaviyo, Mailchimp) do this automatically.
Remove unnecessary whitespace
Minifying your HTML can save 5-15% file size. Remove tab indentation and extra line breaks before sending.
Consolidate repeated styles
If you have 20 <p> tags each with identical style attributes, consider using a <style> block in the <head>. Gmail strips <head> styles for most placements, but for file size purposes, a single declaration in a <style> block is smaller than 20 inline repetitions in the actual email client that does support it.
Check image alt text and long text content
Very long text content or very long alt attribute values add up.
Paginate very long emails
If your email genuinely requires extensive content (newsletters, product roundups), split it into shorter emails sent to different segments.
When clipping is unavoidable
If your email genuinely needs to be long, optimize the order of content: put your most important CTA and content above the likely clip point (~70KB), so subscribers see the key message even if the email clips.
Checking in the Gmail UI
In Gmail web, you can see the actual message size in the original message view:
- Open the email
- Click the three-dot menu → "Show original"
- The source page shows the message size in bytes at the top