# Email attachment size limits: Gmail, Outlook, iCloud Mail and Yahoo

Source: https://help.strongfolder.com/en/guides/email-attachment-size-limits/
Updated: 2026-11-05

> Email attachment size limits are small: Gmail and Yahoo Mail allow 25 MB per message, iCloud Mail 20 MB, and Microsoft's pages give 20–25 MB for Outlook.com. Work accounts follow their admin's settings. For anything bigger, send a link instead — a cloud drive, Mail Drop (5 GB), a transfer service, or a direct P2P link such as StrongFolder.

Email is still the default way to send a file — until the file is a few megabytes too big.
This page lists the current email attachment size limits of the main providers, explains why
an attachment under the limit can still bounce, and compares the workarounds when a file is
too big for email.

**Key facts**

- **Gmail:** 25 MB per message; bigger files become a **Google Drive link**.
- **Outlook.com:** Microsoft's pages say **20 MB** or **25 MB**; OneDrive files attach as links **up to 2 GB**.
- **iCloud Mail:** 20 MB, or up to **5 GB with Mail Drop** (links last 30 days).
- **Yahoo Mail:** 25 MB total per message. **Proton Mail:** 25 MB.
- Encoding makes attachments **about a third larger** — keep them well under the limit.
- For bigger files, **send a link**: cloud, transfer service, or a direct StrongFolder link with no size cap from the service.

## What are the attachment size limits of each email provider?

Limits for personal accounts as of 2026-11-05, from each provider's own help pages.

| Provider | Attachment limit per message | Built-in way for bigger files | Notes |
|---|---|---|---|
| Gmail | 25 MB | Google Drive link, inserted automatically | Workspace limits set by the admin |
| Outlook.com | 20 MB or 25 MB (Microsoft pages differ) | OneDrive file as link, up to 2 GB | Free Microsoft accounts have 5 GB of OneDrive storage |
| Outlook with Microsoft 365 (work/school) | Set by your organisation | OneDrive / SharePoint link | Ask your IT admin |
| iCloud Mail | 20 MB | Mail Drop, up to 5 GB, 30-day links | Mail Drop has its own 1 TB storage limit |
| Yahoo Mail | 25 MB total | Share a cloud link | Applies to incoming and outgoing mail |
| Proton Mail | 25 MB (outgoing) | Proton Drive link | Same on free and paid plans |

Two practical rules follow from this table: anything above **20 MB** is risky to attach no
matter which provider you use, and every provider's answer for bigger files is the same —
**send a link**.

## Why does an attachment under the limit still fail?

Three reasons, in order of how often they bite:

1. **Encoding overhead.** Email was designed for text, so attachments are converted to text
   (Base64) for transport. That makes them roughly a third larger: an 18–19 MB file can
   already fill a 25 MB message.
2. **The recipient's limit.** Your provider may accept 25 MB, but the recipient's company
   server may stop at 10 MB. The message bounces on their side.
3. **The whole message counts.** Limits apply to the total of all attachments plus the body —
   three 9 MB files in one email are 27 MB.

## Is the limit per file or per email?

Per email. Gmail and Yahoo state the limit as the total of all attachments in one message. You
can send several emails with a few files each, but for more than a handful of files that gets
messy fast — the recipient has to collect and reassemble everything.

## What are the workarounds when a file is too big for email?

| Workaround | Size it handles | Effort for you | Effort for the recipient | Stored on a server? |
|---|---|---|---|---|
| Compress the file (PDF, images) | Gets a few MB under the limit | Low | None | In mailboxes |
| ZIP the files | Small gain; almost none for photos and video | Low | Extract the ZIP | In mailboxes |
| Split across several emails | Tens of MB | High | Collect all parts | In mailboxes |
| Cloud drive link (Drive, OneDrive, Dropbox) | Your storage quota | Upload first | Click a link | Yes, until deleted |
| iCloud Mail Drop | 5 GB | Upload first | Click a link (30 days) | Yes, 30 days |
| Transfer service (WeTransfer free) | 3 GB per transfer | Upload first | Click a link (3 days) | Yes, 3 days |
| **StrongFolder link** | **No limit set by the service** | **None — no upload** | **Click a link** | **No** |

### Shrink the file

For a PDF that is just over the limit, shrinking is the quickest fix: Acrobat's *Reduce File
Size*, the *Reduce File Size* filter in macOS Preview, or *Compress Pictures* in Office before
exporting. Details in [how to send large documents](https://help.strongfolder.com/en/guides/send-large-documents/).

### Use your provider's built-in link

Gmail does this automatically with Google Drive, Outlook.com with OneDrive, and iCloud Mail with
Mail Drop. It is the path of least resistance, but the file uses your cloud storage and a copy
stays on the provider's servers.

### Paste a direct transfer link into the email

With StrongFolder you don't attach or upload anything. Choose the file or folder, copy the link
and paste it into your email. When the recipient clicks it, their browser downloads straight
from yours over an encrypted connection. Files are never uploaded to or stored on a StrongFolder server. No size limit set by StrongFolder. The practical limits are free disk space on the recipient's device, connection speed, and how long both devices stay online.

The one condition: The sender's browser tab must stay open and online until the recipient finishes downloading — files come from the sender's device, not from a server. If you send the email at night and the recipient
reads it in the morning, use a cloud link instead.

[Send files now](https://strongfolder.com)
## Can I increase my email attachment size limit?

Not on a personal account — the limits are fixed by the provider. On business accounts
(Google Workspace, Microsoft 365) administrators can raise or lower the limits within what the
provider allows. Even then, the message must also fit the **recipient's** server, which you
don't control. That is why sending a link is the reliable answer for anything large.

## When should I still attach the file?

Attach it when it is comfortably small (a few MB), when the recipient needs the file inside
the email thread for records, or when their organisation blocks cloud links. For anything
else — videos, photo sets, large PDFs, whole folders — a link is faster and more reliable. See
[how to send large files](https://help.strongfolder.com/en/guides/send-large-files/) for every method by size, and
[how to send large video files](https://help.strongfolder.com/en/guides/send-large-video-files/) for footage.

## Summary

Email attachment size limits sit between 20 and 25 MB for every major provider, and encoding
eats about a third of that. For bigger files, send a link in the email: your provider's cloud
link if you can't stay online, or a direct StrongFolder link if you want no upload, no size cap
from the service and no copy left on a server.

## FAQ

### What is the Gmail attachment size limit?

25 MB per message for personal Gmail accounts. If your attachments go over it, Gmail removes them and inserts a Google Drive link instead. In Google Workspace the administrator sets the limits.

### What is the Outlook attachment size limit?

Microsoft's help pages give 20 MB in one article and 25 MB in another for Outlook.com. Files stored in OneDrive can be attached as links up to 2 GB. Work and school accounts follow their organisation's settings.

### Why does my 22 MB attachment fail when the limit is 25 MB?

Attachments are encoded for transport, which makes them roughly a third larger than on disk, and the recipient's server may have a lower limit than yours. Keep attachments well under the limit, or send a link.

### Is the limit per file or per email?

Per message. Gmail and Yahoo count the total of all attachments in one email, so three 10 MB files will not go through in one message.

### Can I increase my email attachment limit?

Not on personal accounts. On business accounts (Google Workspace, Microsoft 365) an administrator can change the limits within the provider's maximum, but the recipient's server must accept the size too.

### How do I send a file that is too big for email?

Send a link in the email instead of the file: a cloud drive share, iCloud Mail Drop (up to 5 GB), a transfer service, or a StrongFolder link, which has no size limit set by the service and stores nothing on a server.