Free tool
Email Size Calculator
Paste your email content to estimate its size, see whether Gmail will clip it, and get recommendations to slim it down.
Attachment size check
Add the size of each attachment to check the total against Gmail's 25 MB sending limit.
This free email size calculator estimates how many kilobytes your email weighs before you send it. Gmail cuts off any message larger than about 102 KB and hides the rest behind a "[Message clipped] View entire message" link, which buries your content, your unsubscribe link, and often your open-tracking pixel. Paste your HTML or plain text above, check the verdict, and apply the recommendations until your campaign fits comfortably under the limit.
How to use the email size calculator
- 1
Copy the full HTML source of your email, or the plain text version if that is what you send.
- 2
Paste it into the box above and click "Calculate size".
- 3
Read the estimated size and the progress bar against Gmail's 102 KB clipping threshold.
- 4
Apply the recommendations: remove unused markup, host images externally, and shorten the message if needed.
- 5
Paste the trimmed version and recalculate until the verdict says your email is safe.
Frequently asked questions
Why does Gmail clip my email?
Gmail truncates any message whose body is larger than roughly 102 KB and replaces the rest with a "[Message clipped] View entire message" link. This keeps the inbox fast, but it means subscribers only see part of your email unless they click through. Keeping the HTML under the limit is the only reliable way to avoid it.
What counts toward the email size?
Everything in the message body counts: text, HTML tags, inline CSS, tracking snippets, and any base64-encoded images. Attachments are counted separately and do not trigger clipping, but they are subject to Gmail's 25 MB sending limit. Linked images hosted on a server only contribute the length of their URL.
How do I reduce the size of my email?
Start by removing markup you do not need: leftover tags from your editor, deeply nested tables, repeated inline styles, and commented-out blocks. Host images on a public server instead of embedding them, shorten your copy, and avoid pasting content straight from Word or Google Docs, which adds heavy hidden formatting.
Do images make my email heavier?
It depends how they are included. An image referenced by URL adds only a few dozen bytes to the HTML, no matter how large the file is. An image embedded as base64 data lands entirely inside the body and grows it by about a third more than the original file size, which is the fastest way to get clipped.
What is Gmail's attachment limit?
You can send up to 25 MB of attachments per message in Gmail. If your files exceed that, Gmail automatically uploads them to Google Drive and inserts a sharing link. Note that receiving limits differ: Gmail can accept incoming messages up to 50 MB.
Does clipping affect open tracking and unsubscribe links?
Yes, and that is why senders care so much about it. Tracking pixels are usually placed at the very end of the HTML, so when Gmail clips the message the pixel never loads and the open is not recorded. Unsubscribe links in the footer get hidden too, which frustrates recipients and can increase spam complaints.
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