The fastest way to attach a file

Open your email in Outlook and look for the paperclip icon in the toolbar at the top of the compose window. Click it, then select the file you want to attach from your computer. Outlook will add it to your email immediately. You can attach multiple files by clicking the paperclip again and selecting another file.

If you don't see the paperclip icon, you may be using Outlook on the web. In that case, look for a plus sign (+) or attachment icon near the bottom of the compose area. Click it and choose your file the same way.

The file stays attached until you send the email. If you change your mind, hover over the filename and click the X to remove it before sending.

Key Takeaways

  • Click the paperclip icon in the compose toolbar to attach a file from your computer.
  • You can attach multiple files to one email by clicking the paperclip repeatedly.
  • Outlook on the web uses a plus sign or attachment icon instead of a paperclip.
  • Remove an attachment by hovering over the filename and clicking the X before you send.
  • File size limits depend on your email provider, but most allow attachments up to 20 or 25 megabytes.

Where to find the attachment button in different Outlook versions

The location of the attachment button changes slightly depending on which version of Outlook you use. In Outlook for Windows (the desktop program), the paperclip is in the toolbar at the top of the compose window, usually near the formatting buttons. In Outlook for Mac, it's in the same place but may look slightly different depending on your macOS version.

In Outlook on the web (the version you access through a browser), the attachment button appears near the bottom of the compose area, often grouped with other options like inserting a table or adding a signature. Look for a plus sign, a paperclip, or a label that says "Attach."

If you're using Outlook mobile on your phone or tablet, tap the paperclip icon or the plus sign at the bottom of the compose screen. The exact location depends on whether you have an iPhone, Android, or iPad.

File size limits and what happens if your file is too large

Most email providers limit attachment size to between 20 and 25 megabytes per file. If your file is larger, Outlook will usually warn you before you send. Some providers are stricter — Microsoft 365 accounts, for example, allow up to 34 megabytes, while some corporate email systems may have smaller limits.

If your file exceeds the limit, you have two options. You can compress the file to make it smaller by right-clicking it in Windows (or using the Compress option on Mac) and selecting "Send to compressed folder." Alternatively, you can upload the file to cloud storage like OneDrive, Google Drive, or Dropbox and send a link instead of attaching the file itself.

Outlook also has a feature called Outlook file attachment compression that automatically reduces image quality when you attach photos. This happens without your input and can help keep emails under the size limit.

Attaching files from cloud storage instead of your computer

You don't have to store files on your computer to attach them. In Outlook on the web and Outlook for Windows, you can attach files directly from OneDrive, SharePoint, or other cloud services. Click the attachment button and look for an option that says "Browse cloud locations" or "OneDrive." Select the file from your cloud storage and Outlook will insert it.

When you attach a file from OneDrive, Outlook gives you the choice to send a copy of the file or a link to it. Sending a link is useful if the file is large or if you want the recipient to always see the most recent version. Sending a copy means the recipient gets a standalone file that won't update if you change the original.

This feature is not available in Outlook for Mac or Outlook mobile, so you'll need to download the file to your device first and then attach it the usual way.

Dragging and dropping files into your email

In Outlook for Windows and Outlook on the web, you can drag a file directly from your computer into the compose window instead of using the attachment button. Open a file explorer window (or Finder on Mac) alongside your email, then drag the file into the email body or the attachment area. Outlook will recognize it as an attachment automatically.

This method works for most file types, but the exact behavior depends on your version of Outlook. In some versions, dragging a file into the email body inserts it as an image or embedded object rather than an attachment. To be sure the file attaches as a downloadable file, drag it into the attachment area specifically, not into the message text.

Dragging and dropping does not work in Outlook mobile or in some older versions of Outlook for Mac, so stick with the attachment button if this method doesn't work for you.

What file types Outlook accepts and common problems

Outlook accepts most common file types: documents (Word, PDF, Excel), images (JPG, PNG, GIF), videos, audio files, and compressed folders (ZIP files). However, some file types are blocked for security reasons. Executable files (.exe), script files (.bat, .cmd), and certain other formats cannot be attached in most corporate email systems.

If you're trying to attach a blocked file type, you'll see an error message when you try to send. The solution is to compress the file into a ZIP folder first. Right-click the file, select "Send to," then choose "Compressed (zipped) folder." Attach the ZIP file instead. The recipient can then unzip it on their end.

Another common problem is that the file appears to attach but then disappears before you send. This usually means Outlook encountered an error reading the file. Try closing and reopening Outlook, or restart your computer. If the problem persists, the file itself may be corrupted — try attaching a different file to confirm.

Frequently Asked Questions

Can I attach a file that's currently open in another program?

Yes, you can attach a file even if it's open in Word, Excel, or another program. Outlook doesn't lock files while you're composing an email. However, if you're editing the file and haven't saved your changes, the recipient will get the last saved version, not your current work. Save the file first to make sure they receive the latest version.

What's the difference between attaching a file and inserting it into the email body?

An attachment is a separate file the recipient downloads. Inserting a file into the email body embeds it directly in the message, usually as an image or formatted text. Use attachments when you want the recipient to have the original file. Use insertion when you want them to see the content directly in the email without downloading anything.

Why does my attachment show as a link instead of a file?

If you attached a file from OneDrive or SharePoint, Outlook may have sent a link instead of a copy. This happens automatically in some versions. To send the actual file instead, click the attachment and look for an option to "Download" or "Send as copy" before you send the email.

Can I attach a folder instead of individual files?

Most versions of Outlook don't allow you to attach a folder directly. Compress the folder into a ZIP file first by right-clicking it and selecting "Send to compressed folder," then attach the ZIP. The recipient can unzip it to access all the files inside.

Is there a limit to how many files I can attach to one email?

There's no hard limit on the number of files, but the total size of all attachments combined cannot exceed your email provider's limit (usually 20 to 25 megabytes). If you need to send many large files, compress them into a ZIP or use cloud storage links instead.