The fastest way to send a zip file in Outlook
To send a zip file in Outlook, attach it the same way you would attach any other file: click the paperclip icon in your message, browse to the zip file on your computer, and select it. Outlook treats zip files like regular attachments — there is nothing special about the process. The zip file will appear in your message as an attachment, and the recipient will download it when they open your email.
The main reason to use a zip file is size. If you are sending multiple documents or large files, zipping them first compresses them into one smaller package, which means faster uploads and downloads. Outlook has a 20 MB attachment limit per message on most accounts, so a zip file can help you stay under that cap when you have a lot to send.
Key Takeaways
- Click the paperclip icon in a new Outlook message, then select the zip file from your computer — no special steps are needed.
- Zip files compress multiple documents into one smaller file, which helps you send more content without hitting Outlook's 20 MB size limit.
- If Outlook warns that your attachment is too large, create a zip file first to reduce the total size before attaching.
- The recipient receives the zip file as a download and must unzip it on their end to see the individual files inside.
Attaching a zip file in Outlook on Windows
Open Outlook and start a new email message. Click the Attach File button — it looks like a paperclip and is usually in the toolbar near the top of the message window. A file browser window will open.
Navigate to the folder where your zip file is stored. Click the zip file once to select it, then click the Insert button at the bottom right of the browser. The zip file will now appear in the Attachments section of your message, usually shown as a small icon with the filename next to it. Type your message, add recipients, and send as normal.
Attaching a zip file in Outlook on Mac
Open Outlook and create a new message. In the menu bar at the top, click Insert, then select Attach File from the dropdown. A file browser will appear on your screen.
Find your zip file in the browser, click it once to select it, then click Insert. The attachment will show in your message. Complete your email and send it. If you do not see an Insert menu, look for a paperclip icon in the message toolbar instead — clicking it opens the same file browser.
Creating a zip file before you send it
If you do not yet have a zip file and need to create one, the process is different on Windows and Mac. On Windows, right-click the file or folder you want to zip, then select Send to and choose Compressed (zipped) folder. Windows will create a new zip file in the same location with a name like "Folder.zip" or "Document.zip".
On Mac, right-click the file or folder and select Compress from the menu. Mac will create a zip file with the same name plus ".zip" at the end. Once the zip file exists, follow the attachment steps above to send it through Outlook.
What to do if your zip file is still too large
Even after zipping, your file might still exceed Outlook's 20 MB limit. Check the file size by right-clicking the zip file and selecting Properties (Windows) or Get Info (Mac). If it shows larger than 20 MB, you have two options: split the zip into smaller pieces, or use cloud storage instead.
To split a zip file, you can use free tools like 7-Zip on Windows or Archive Utility on Mac, which allow you to create multiple smaller zip files from one large folder. Alternatively, upload your zip file to OneDrive, Google Drive, or Dropbox, then send your recipient a link to download it from there instead of attaching it to the email. This method is often faster for very large files.
Why your recipient might not be able to open the zip file
Most computers come with built-in tools to unzip files, so your recipient should be able to open what you send without installing anything extra. On Windows, they can right-click the zip file and select Extract All. On Mac, they can double-click the zip file and it will unzip automatically.
If your recipient says they cannot open the zip file, the most common cause is that their email client blocked it or it did not download completely. Ask them to check their Downloads folder and try again. If the file is corrupted during upload, you may need to resend it or use a cloud storage link instead. Some corporate email systems also block zip files for security reasons — if that is the case, your recipient's IT department can tell them whether they need to use a different method to receive the file.
Frequently Asked Questions
Can I send a zip file that contains another zip file?
Yes, you can nest zip files inside other zip files without any problem. Your recipient will need to unzip the outer file first, then unzip the inner one. This is rarely necessary, but it works if you need to organize files that way.
Does Outlook automatically zip files when I attach them?
No. Outlook attaches files exactly as they are. If you want a zip file, you must create it yourself before attaching it. Outlook will not compress files for you.
What is the difference between a zip file and a regular attachment?
A zip file is compressed, which makes it smaller and faster to send and download. A regular attachment is sent at full size. If you are sending one small document, there is no real benefit to zipping it first. Zipping helps when you have multiple files or large files to send together.
Will my recipient need special software to open a zip file?
No. Windows and Mac both include built-in tools to unzip files. Your recipient does not need to install anything or pay for software. They simply right-click (Windows) or double-click (Mac) the zip file to open it.
Can I password-protect a zip file before sending it?
Yes, but the process depends on your operating system. On Windows, some zip tools like 7-Zip allow you to add a password when creating the zip. On Mac, you can use the command line or third-party tools. Once password-protected, your recipient will need the password to unzip the file. You should send the password separately, not in the same email as the zip file.