How big can an HTML email be?
Keep the raw HTML under ~100 KB to avoid Gmail clipping and deliverability hits. Inline styles and tracking markup add up fast-minimize repetition and strip unused code.
Key Takeaways
- ✓ Target <100 KB HTML; Gmail clips near 102 KB.
- ✓ Compress inline styles and remove unused tables.
- ✓ html2email flags documents approaching the limit.
Keep the raw HTML under ~100 KB to avoid Gmail clipping and deliverability hits. Inline styles and tracking markup add up fast-minimize repetition and strip unused code.
| HTML size | Gmail |
|---|---|
| Under ~100 KB | Full message shown |
| Over ~102 KB | Clipped; “View entire message” link |
Keep HTML under ~100 KB to avoid Gmail clipping.
What is Gmail’s clipping limit?
Around 102 KB of HTML. Anything beyond is truncated with a “View entire message” link, hiding CTAs and tracking pixels.
How do I measure HTML size?
Export the final HTML from your ESP and check file size. Minify safely or remove whitespace if needed, but keep readability during editing.
What makes HTML bloat?
Repeated inline styles, large tracking URLs, unused template modules, and embedded base64 assets. Reuse classes and partials where possible.
How does html2email detect large documents?
The DocumentSizeValidator counts bytes and flags when size exceeds the recommended limit, including inline styles and comments.
How can I shrink HTML safely?
Remove unused tables, deduplicate inline styles, shorten URLs, avoid base64 images, and collapse whitespace before sending.
Do images count toward the 100 KB?
Only inline/base64 images do. Linked images do not count toward HTML size but still affect load time.
Does minification harm deliverability?
No, if done carefully. Avoid breaking inline CSS and ensure line breaks remain where ESPs require them.
What about multipart/alternative?
Keep text part lean too. Large HTML plus text can increase spam score; trim both.
Gmail clipping notice on large email.
Key stats and sources
- Gmail clipping begins around 102 KB of HTML.
- Internal QA: trimming inline style repetition reduced HTML size by 18–30% per campaign.
- html2email flags size overruns so you can shrink before sending.
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