Microsoft offers 15 GB of email storage space per free Outlook.com account. Office 365 Home and Office 365 Personal subscribers get 50 GB of space.
"Quota Exceeded, your account is above quota limits"
If your mailbox is full, we will send you a message telling you that your account is above quota limits, and you won't be able to send or receive any messages. Also, people who send you email will receive an error message that tells you your mailbox is full.
To see how much mailbox storage you've used:
At the top of the page, select Settings > View all Outlook settings.
Select General > Storage.
Empty Deleted Items
Email in your Deleted Items folder counts towards your mailbox size. You can empty your Deleted Items folder by selecting the folder and choosing Empty folder.
Tip: In some cases, you may also need to delete all your recoverable items, too. Go to Deleted Items and select Recover items deleted from this folder and select Empty folder.
How to permanently delete email
To permanently delete a message or messages, select or highlight the messages, press Shift and DEL on your keyboard.
Reduce your storage
To make room in your mailbox, try the following solutions.
Empty your Junk Email folder by selecting the folder and selecting Empty folder.
Use the Sweep button to quickly remove unwanted email from your inbox or archive folders. Sweep lets you automatically delete all incoming email from a particular sender, keep only the latest message from that sender, or delete email that's older than 10 days.
To sweep your inbox, choose a message you want to sweep, and select Sweep.
To learn more about Sweep, see Organize your inbox with Archive, Sweep, and other tools in Outlook.com.
Saving photos and documents to OneDrive is another good way to make room in your inbox.
At the top of your message list, select Filter > Sort by > Size.
Note: If the message list sorts the smallest messages on top, click Filter > Sort by > Size again to put the largest messages on top.
Select the message containing the attachments you want to upload to OneDrive.
Beneath the attachment, select Save to OneDrive.
To delete the file or image, you must delete the message it's attached to:
For All images, find the corresponding message in your mailbox and delete it.
For Sent images, go to your Outlook.com Sent Items, find the corresponding message, then delete it.
After deleting the message, you also need to delete it from your Deleted Items folder. Go to Deleted Items, select the item or items to remove, then select Delete.
Note: If the message is important, save the images to your computer or OneDrive, forward the message to yourself without the images, then delete the original message.
How else can I increase sending and storage limits?
You can increase sending and storage limits by upgrading your Outlook.com account with an Office 365 subscription. This gives you:
Advanced email security
An ad-free inbox
A 50 GB mailbox per person