Gmail attachment size limit: 25 MB, which is really about 18 MB
Short answer
Gmail lets you send up to 25 MB of attachments per email and receive up to 50 MB. Because email encoding adds about a third, only about 18 MB of real files fit in one message.
| Limit | |
|---|---|
| Sending (all attachments in one email) | 25 MB |
| Receiving | 50 MB |
| Real file size that fits when sending | About 18 MB |
| Paying for more Google storage | Doesn’t change either limit |
Why 25 MB is really about 18 MB
Email was designed for text, so attachments are converted into text (base64 encoding) before they're sent. That makes every attachment about 33% bigger. A 20 MB PDF becomes roughly 27 MB in transit, which is over the limit, and Gmail refuses it even though the file itself looks well under 25 MB.
What Gmail does with bigger files
Attach something over the limit and Gmail uploads it to Google Drive and puts a Drive link in the email instead. That works, with some downsides:
- The file counts against your 15 GB of free Google storage, shared with Gmail and Photos.
- On a personal Google account, a shared Drive link doesn't expire. The file stays reachable until you remember to delete it.
- You have to get the sharing permissions right, or the recipient hits "request access".
A simpler way to send large files by email
Upload the file to Send Shed's Quick Share (free, no account, up to 3 GB per file) and paste the link into your email. Choose when it expires and how many times it can be downloaded, and add a password if you want. Nothing lands in your Google storage. For tax documents, contracts or anything else sensitive, use Encrypted Share: the file is encrypted in your browser before upload, so not even we can open it.
Quick answers
What is Gmail's attachment size limit?
You can send attachments up to 25 MB in total per email and receive up to 50 MB.
Why does Gmail say my 20 MB file is too big?
Email encodes attachments in a way that makes them about a third larger, so a 20 MB file becomes about 27 MB in transit, over the 25 MB limit. In practice about 18 MB of files fit.
What happens if my Gmail attachment is over 25 MB?
Gmail uploads the file to your Google Drive and inserts a Drive link instead. The file counts against your 15 GB Google storage, and the link does not expire on its own.
Too big? Send it here instead
Upload it to Quick Share — up to 3 GB per file, free, no account — and paste the link wherever you were trying to attach it. The link expires on its own.
Send it with Quick Share Send it encrypted