To attach a file to a message you're composing, follow the steps below:
In Gmail, click the Compose button.
Click the paperclip icon at the bottom of the compose window.
Browse through your files and click the name of the file you'd like to attach.
To attach multiple files, hold the Ctrl (PC) or ⌘ (Mac) key while selecting your files. Selecting multiple files at once is not possible using Internet Explorer 9.
Tip: Drag and drop attachments directly into the compose window.
When you drag and drop images, you can add the images inline in the message or as attachments.
If you'd like to remove a file you've attached to a message, click the x to the right of the file name at the bottom of the message.
More insert options
Hover over the + icon to insert files from Google Drive and embed photos, links, emoticons, and Google Calendar events.
Attachment size limit
You can send messages up to 25 megabytes (MB) in size. If you’d like to send attachments that are larger than this, you can insert from Google Drive instead.
You may not be able to send larger attachments to contacts who use other email services with smaller attachment limits. If your attachment is too large to be sent to your contacts, you can also insert using Google Drive to get larger files to them. (You can also invite them to Gmail).
As a security measure to prevent potential viruses, Gmail doesn't allow you to send or receive executable files (such as files ending in