Gmail — web, iOS and Android — truncates any email whose HTML exceeds roughly 102KB. Recipients see your message cut off mid-content with a small “[Message clipped] View entire message” link. Most people never click it.
Why clipping is worse than it sounds
- Your unsubscribe link disappears. It usually lives in the footer — the first thing clipping hides. Frustrated readers click “Report spam” instead, damaging your sender reputation.
- Open tracking can break, since tracking pixels are typically injected at the end of the message.
- Your call to action may never be seen if it sits low in the layout.
What counts toward 102KB
Only the HTML source itself — images are not counted (they load separately), but their markup is. The usual culprits are bloated markup from design tools, repeated inline styles, and long messages that should have been web pages.
How to stay under the limit
- Keep marketing emails to one job: a teaser that links out, not the whole story.
- Use a builder that emits lean markup and shows you the size as you work — our free editor has a live size meter that warns you long before 102KB.
- Don't paste from Word or Google Docs into HTML editors; the generated markup is enormous.
- If you A/B test, remember some ESPs append per-variant markup — leave headroom (we warn at 80KB).