Hotmail Attachment Size Limit
Hotmail addresses now use Outlook.com, but the practical attachment problem is the same: your file has to fit the email service, the full message, and the recipient’s mailbox. Use this guide to check the limit, choose a safe target, and decide whether to compress the file or send a OneDrive link.
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Last updated: May 27, 2026
Quick answer
- Hotmail addresses are handled through Outlook.com.
- Microsoft lists a 25 MB size limit for an Outlook.com email, including text, inserted files, and attachments.
- For normal attachments, aim below 20 MB so the message has room to send safely.
- If the file is larger, compress it first or attach it as a OneDrive link.
For the broader Microsoft workflow, see Compress Photos for Email Outlook and Compress File for Email.
Check the file first
Choose the file before you decide whether to compress it, split it, or send a OneDrive link. The checker gives you the size result and shows whether the file is likely to fit a safer email target.
Pick the PDF, image, or video you want to email. The size check is free.
Email size result
- Files
- Not selected
- Total size
- 0 MB
- Email service
- Most email services
- Safe email target
- Safe target: 20 MB
- Compression needed
- Choose a file and we will show this.
Your result will appear here after you choose a file.
Optional
Sending to work or school?
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You can leave this empty. It is only here if you want to check a work, school, or company email address.
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Go to: Hotmail limit · Safe target · If it is too large · File types · OneDrive links · Troubleshooting · FAQ
What is the Hotmail attachment size limit?
Hotmail is now part of Outlook.com. For Outlook.com, Microsoft says the size limit for an email is 25 MB. That includes all message text, inserted files, and attached files. In practice, this means one file near 25 MB can be risky, and several smaller files can fail together when the full message becomes too large.
Microsoft also documents a 20 MB email size limit for many internet email accounts in Outlook. That is why a 20 MB working target is safer than trying to attach a file that is right below 25 MB. The exact result can depend on the account, the app, the recipient, and whether a company or school policy is involved.
Use a safe target, not the maximum number
The safest attachment is smaller than the published limit. A file under 10 MB is usually comfortable. A file between 10 MB and 20 MB is often reasonable if it is the main attachment. A file between 20 MB and 25 MB may work in Outlook.com, but it leaves less room for the message itself and for the recipient’s mail system.
| File size | Hotmail / Outlook.com risk | Best next step |
|---|---|---|
| Under 10 MB | Usually comfortable | Attach normally after checking the file. |
| 10-20 MB | Usually workable | Attach if this is the main file. |
| 20-25 MB | Riskier | Compress first if the recipient needs an attachment. |
| Over 25 MB | Usually too large | Compress, split, or use a OneDrive link. |
What happens if a Hotmail attachment is too large?
Outlook.com may refuse the attachment, leave the message stuck, or push you toward a OneDrive link. A OneDrive link can be the right answer for large files, but it is not the same as a normal attachment. The recipient opens a shared file instead of receiving the full file inside the email.
- Check the file size before attaching it.
- If the file is near 20-25 MB, make a smaller copy first.
- If the file is much larger, decide whether the recipient can use a link.
- If using OneDrive, check sharing permissions before sending.
- If a true attachment is required, compress or split the file instead.
Compress the right file type first
PDFs
PDFs become large when they contain scanned pages, photos, charts, or high-resolution images. Start with Compress PDF for Email, or use Scanned PDF Too Large to Email if the document came from a scanner.
Photos
Photos are usually best reduced by resizing dimensions and saving a smaller JPG copy. For Microsoft mail workflows, see Compress Photos for Email Outlook.
Videos
Videos are often too large for normal email. Trim the clip, export a smaller MP4, or send a link when the recipient needs the original quality.
When to use OneDrive instead of a Hotmail attachment
Microsoft says OneDrive links do not count toward the Outlook.com email size limit, and linked files can be much larger than normal attachments. Use OneDrive when the file is large, the recipient can open a link, or quality matters more than forcing the file into a small attachment.
Use a normal attachment when the recipient specifically asked for one, when the file is already small, or when the recipient cannot use shared links. If you paste or attach a link, open the sharing settings and make sure the recipient can access it.
Troubleshooting Hotmail attachment problems
| Problem | Likely cause | What to do |
|---|---|---|
| Outlook.com will not add the attachment | The file or full message is too large | Compress the file or use OneDrive. |
| The message is stuck | The attachment is too close to the limit | Remove it, make a smaller copy, and try again. |
| Recipient cannot open the link | Sharing permissions are too narrow | Adjust OneDrive permissions or send a smaller attachment. |
| Photos are too large | Original camera dimensions are unnecessary for email | Resize and send smaller JPG copies. |
| PDF is still too large | Scans or embedded images dominate the size | Compress scans, remove extra pages, or send a link. |
Final checklist
- The file is below a safe target, preferably under 20 MB for normal attachments.
- The file opens correctly after compression.
- Photos, scans, signatures, and small text are still readable.
- The recipient can use the format you are sending.
- OneDrive links have the right sharing permissions.
FAQ
Does Hotmail still exist?
Hotmail addresses still exist, but they are handled through Outlook.com. The attachment behavior you see today is Outlook.com behavior.
What is the Hotmail attachment size limit?
For Outlook.com, Microsoft lists a 25 MB email size limit that includes message text, inserted files, and attachments. A safer working target is below 20 MB.
Can I send a file larger than 25 MB from Hotmail?
Not as a normal Outlook.com attachment. Use OneDrive or another sharing method, or make a smaller copy if the recipient needs an attachment.
Does OneDrive count toward the Hotmail attachment limit?
Microsoft says OneDrive links do not count toward the Outlook.com email size limit. The recipient receives a link, not the full file as a normal attachment.
Why did Outlook.com reject a file under 25 MB?
The full message may be larger than the file alone, or the recipient’s system may be stricter. If the file is close to the limit, compress it or send a link.
Should I compress a PDF or use OneDrive?
Compress the PDF when the recipient needs a normal attachment. Use OneDrive when the file must stay sharp, is too large to compress cleanly, or can be delivered as a link.