The basic way to attach a file

To attach a file to an email, look for a paperclip icon or an "Attach" button in your email program. Click it, then browse your computer to find the file you want to send. Select the file and click "Open" — the file name will appear in the attachment area of your email. Then write your message and send as usual.

The paperclip icon is standard across most email services: Gmail, Outlook, Yahoo Mail, and Apple Mail all use it. If you cannot find it, look near the bottom of the compose window or in a menu labeled "Insert" or "Options." Some email programs let you drag and drop files directly into the message instead of using the button.

Before you send, check that the file actually attached. Look for the file name listed below the subject line or in a dedicated attachments section. This takes two seconds and prevents the awkward "I forgot to attach it" email you have to send later.

Key Takeaways

  • Click the paperclip icon or "Attach" button, browse to your file, and select it — the file name will appear in your compose window.
  • Check that the attachment actually appears before you send the email, because forgetting to attach is one of the most common email mistakes.
  • File size limits vary by email service: Gmail allows up to 25 MB per file, Outlook allows 20 MB, and Yahoo Mail allows 25 MB.
  • If your file is too large, compress it first or use a file-sharing service like Google Drive or Dropbox instead of attaching it directly.
  • On a phone or tablet, the attachment button may be hidden in a menu — look for three dots or a plus sign in the compose area.

Understanding file size limits

Every email service has a maximum file size it will accept. Gmail allows up to 25 MB per attachment. Outlook allows 20 MB. Yahoo Mail allows 25 MB. If your file is larger than the limit, the email will not send and you will see an error message.

A typical document or photo is well under these limits. A Word document is usually 1 to 5 MB. A photo from a phone camera is typically 2 to 8 MB. Video files are much larger — a one-minute video can easily be 50 MB or more, which means it will not fit in most email systems.

If you need to send a large file, compress it first. On Windows, right-click the file, select "Send to," then "Compressed (zipped) folder." On Mac, right-click and select "Compress." Compression can reduce file size by 50 percent or more, though it works better on some file types than others. If compression is not enough, use a file-sharing service instead.

Using file-sharing services for large files

If your file is too large to attach, upload it to Google Drive, Dropbox, OneDrive, or a similar service instead. Then send an email with a link to the file. The recipient clicks the link and downloads it from the service.

This method has advantages beyond size. The recipient does not have to wait for a large download, and you can change who has access to the file after you send the email. If you share a file by attachment and then realize you made a mistake, that file is already in someone else's inbox. If you share a link, you can revoke access immediately.

Most file-sharing services offer free accounts with enough storage for occasional use. Google Drive gives 15 GB free. Dropbox gives 2 GB free. OneDrive gives 5 GB free. If you regularly send large files, a paid plan costs a few dollars per month.

Attaching files on a phone or tablet

On a phone or tablet, the attachment button is often hidden because screen space is limited. In Gmail on iPhone or Android, open a new email and look for a paperclip icon or a plus sign at the bottom of the screen. Tap it and select "Attach file." You will then browse your phone's files or photos.

On Outlook mobile, tap the three dots menu in the compose area, then select "Attach." On Yahoo Mail mobile, look for a paperclip icon at the bottom. The exact location varies slightly between iPhone and Android, and between email services, but the concept is the same: find the menu, tap attach, and browse to your file.

Attaching from a phone works best with files you already have stored there — photos, documents you downloaded, or files from cloud storage. If the file is on your computer, upload it to Google Drive or Dropbox first, then attach the link instead of trying to transfer it through email.

Common attachment problems and how to fix them

The most common problem is attaching the wrong file. Before you send, read the file name in the attachments section. If it is wrong, click the X next to it to remove it, then attach the correct file.

Another common issue is the file not attaching at all, even though you clicked the button. This usually happens if your internet connection dropped while the file was uploading. Try attaching again, or refresh the page and start over. If it still does not work, try a different file to see if the problem is with that specific file or with your email service.

If the recipient says they cannot open the file, the file may be corrupted or in a format their program does not support. Ask them what error message they see. If the file is a Word document but they only have Google Docs, they can still open it — Google Docs reads most Microsoft formats. If the file is in an unusual format, convert it to a more common one (PDF, JPEG, or DOCX) before sending again.

File types that email services may block

Some email services block certain file types for security reasons. Executable files — programs that run code, like .exe or .bat files — are almost always blocked. Email services do this because these files can contain malware.

If you need to send an executable file or another blocked type, compress it first. Putting the file in a .zip folder often allows it through, though some services block .zip files too if they detect an executable inside. If compression does not work, use a file-sharing service instead.

Most common file types are safe to send: Word documents (.docx), PDFs, images (.jpg, .png), spreadsheets (.xlsx), and videos (.mp4, .mov). If you are unsure whether a file type is blocked, try sending it. If it fails, you will see an error message telling you why.

Frequently Asked Questions

Can I attach multiple files at once?

Yes. Click the attach button and select multiple files from your computer at the same time. Most email services let you select several files in one browse window by holding Ctrl (Windows) or Command (Mac) while clicking each file. You can also attach files one at a time by clicking the attach button multiple times.

What happens if I attach a file and then close the email without sending?

Most email services save your draft automatically. The attachment stays with the draft. When you open the draft again, the file will still be there. If you close the email and do not return to it for a very long time, some services may delete the draft, but this usually takes weeks or months.

Can the recipient forward an email with an attachment?

Yes. When someone forwards your email, the attachment comes along by default. If they do not want to include the attachment, they can remove it before forwarding. This is useful if you want to send a file to multiple people — the first person can forward it to others without you having to send it separately each time.

Is it safe to open attachments from people I do not know?

Be cautious. Attachments are a common way malware spreads. If you receive an unexpected attachment from someone you do not know, especially if the email looks like it is from a company or service you use, do not open it. Scammers often send emails that look official but contain harmful files. When in doubt, contact the sender through another method to confirm they actually sent it.

Why is my attachment showing as a different size than the original file?

Email services sometimes compress files automatically to save space. The file on your computer might be 10 MB, but when it arrives in the recipient's inbox, it may show as 8 MB. The recipient can still open it normally — the compression is temporary and reverses when they download it. This is different from you compressing the file yourself before sending.