Email size calculator
Estimate the size of your message and attachments before sending.
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Everything stays in this tab. Only attachment names and sizes are read, never their contents.
We count tool use, never inputs or results.
Estimated message size
Assumes UTF-8, CRLF line endings and base64 encoding with 76-character lines for each body part and attachment. Includes a fixed allowance for headers and MIME boundaries. Remote images are not downloaded or added; embedded data URLs count as body source.
This is a planning estimate, not the exact message your mail client sends, a delivery guarantee or a Gmail clipping test. Client encoding, headers and provider limits can differ.
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Import your contacts, review personalized messages and manage follow-ups from your own Gmail accounts.