HTML email size checker
Paste your email's HTML to measure its exact size. Gmail clips messages heavier than 102 KB — hiding your footer, unsubscribe link and tracking pixel. This tells you before your subscribers find out.
Why 102 KB matters
Gmail truncates any email whose HTML exceeds roughly 102 KB, showing a 'View entire message' link instead. Everything past the cut — often your footer, unsubscribe link and open-tracking pixel — is hidden, which hurts engagement measurement and can even breach unsubscribe requirements.
This checker measures the exact byte size of the HTML you paste (UTF-8 encoded, the way it's sent) and shows how close you are to the limit.
- Under ~102 KB — the full email renders and tracking fires
- Over the limit — Gmail clips it and hides the tail of your message
- Byte size, not character count, is what counts — this tool measures bytes
Shrinking a heavy email
- Cut redundant inline styles and whitespace; minify the HTML
- Reference images by URL — never embed them as base64
- Remove unused CSS, comments and editor cruft from your template
- Keep the unsubscribe link and footer near the top of the source when you're close to the limit
Frequently asked questions
Is the limit exactly 102 KB?
It's approximately 102 KB (102,400 bytes) of HTML. Staying comfortably below gives you a safety margin, since the exact threshold can vary slightly.
Do images count toward the size?
No — only the HTML source counts, since images are referenced by URL and loaded separately. Embedded (base64) images do count and should be avoided.
Is my HTML uploaded anywhere?
No. The measurement runs entirely in your browser; nothing you paste leaves your device.
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