> ## Documentation Index
> Fetch the complete documentation index at: https://documentation.mysmtp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Email Attachments Size

> Learn mySMTP's email attachment size limit, how Base64 encoding affects file size, and calculate the real maximum attachment size you can send.

The max file size of email attachments is 25 mb

Meaning the real file size can max be around 18MB due to **Base64 encoding**, which adds about **33% overhead**.

This the equation to use: Max file size = 25 MB / 1.33 ≈ 18.75 MB


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