Email attachment size limits, provider by provider
Published on October 4, 2026. 3 min read
Your file is 32 MB, the published limit is 25 MB, and the message will not go. So far, nothing surprising.
You bring it down to 22 MB, under the limit, and it still will not go. That is not a bug. It is how email works, and it deserves one clear explanation.
The published limits
| Service | Limit per message |
|---|---|
| Gmail, personal account | 25 MB |
| Yahoo Mail | 25 MB |
| Outlook.com | around 20 MB, the desktop app applying its own cap |
| iCloud Mail | 20 MB |
| Proton Mail | 25 MB |
| Microsoft 365, business account | 35 MB by default, adjustable by the administrator |
| Corporate mail server | often 10 MB, sometimes less |
These figures change. Check them with your provider when an important message is at stake.
Why your file gets heavier on the way
An email message does not carry your file as it is. It rewrites it into a format made of characters, because email was never designed to carry files.
That rewriting adds about a third in weight. A 20 MB file on your disk becomes close to 27 MB inside the message. That is why a 22 MB file hits a 25 MB limit.
Practical rule. Divide the published limit by 1.4. For a 25 MB limit, aim for 18 MB. For 20 MB, aim for 14 MB.
The limit that matters is not yours
Your provider allows 25 MB, your recipient's allows 10. The lower of the two decides, and you do not know it.
This is the most frustrating case, because the message leaves without an error and the rejection comes later, sometimes minutes later. You think you have sent it, your recipient has nothing.
Practical rule. Below 10 MB, a file goes through almost everywhere. Above that, you are betting on the settings of a server you cannot see.
What the large services do when you go over
Gmail puts the file in Google Drive and inserts a link instead. iCloud does the same with Mail Drop, up to 5 GB, with a link that expires after thirty days. Outlook offers OneDrive.
Convenient, with two caveats. Your recipient can hit a permissions wall if they are outside your organisation. And your document lands in a space that outlives the message, with no deletion date unless you think of it yourself.
Most other servers simply refuse the message.
What to do
Make the document lighter. A PDF weighs mostly through its images. Bringing their resolution down to what a screen displays is often enough to get under the limit, without touching the text. If the document is already as small as it can be, compression will give back almost nothing, and it is better to know that before trying.
Send a link. A download link ignores every limit, yours and your recipient's. It is the only method that works reliably beyond a few tens of megabytes.
Split the document. Four 5 MB attachments go through where one 20 MB attachment fails, provided the document can be split without losing its meaning.
What we do
Levarka compresses your PDF, then gives you a share link, or sends it to the recipient for you. The file and the link are deleted automatically after 24 hours, so nothing lingers in a storage space you forgot about. Compression and storage take place in France.