Email storage & archiving
How email storage works, what your limits are, and how to keep your inbox manageable over the long term.
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Email accumulates fast. After a few years, a business inbox can hold tens of thousands of messages and gigabytes of attachments. This guide covers how storage works, what your limits are, and how to stay organized.
Quick summary
Each email account has a storage limit set by your platform. Google Workspace and Microsoft 365 both offer generous storage per user. What happens when you hit the limit differs between the two: a full Microsoft 365 mailbox stops sending and then stops receiving, while a Google Workspace organization over its pooled limit keeps sending and receiving email and loses the ability to add new content instead — photos straight away, and Drive files and new Docs once it is 25% over or 14 days past the limit. Either way, clear space or upgrade before you get there.
How email storage works
Every email — including attachments — is stored on your email provider's servers. Your email client (Gmail, Outlook) shows you what's stored there. When you delete a message it goes to a trash or deleted-items folder first, and how long it sits there before it's gone for good depends on the platform — see Empty the trash below.
Storage is measured in gigabytes (GB). Most professional email plans include:
| Platform | Storage per user |
|---|---|
| Google Workspace Business Starter | 30 GB per user, pooled across the organization |
| Google Workspace Business Standard | 2 TB per user, pooled across the organization |
| Microsoft 365 Business Basic | 100 GB mailbox + 1 TB OneDrive |
| Microsoft 365 Business Standard | 100 GB mailbox + 1 TB OneDrive |
The two platforms count storage in different ways. Google Workspace shares one pool between Gmail, Drive, and Photos, and the size of that pool is the per-user figure above multiplied by the number of licences — so a heavy Drive user and a light one draw on the same pot. Microsoft 365 gives each person a separate mailbox quota and a separate OneDrive quota, and filling one doesn't affect the other. Other plans give you different amounts — not always more — so check your platform's current plan page for the figures that apply to you.
What happens when you run out of space
This depends on which platform you're on, and the difference matters.
Microsoft 365. As the mailbox approaches its limit, Microsoft starts warning you by email and in Outlook. Once it is full you can't send or receive messages, and people who email you get an error telling them your mailbox is full. You can still sign in and read what's already there.
Google Workspace. Running out of pooled storage does not stop your email. Google says that when an organization is over its limit, people can still sign in, send and receive email, and view and download files. What stops is adding new things: adding photos to Google Photos stops straight away, and once you are 25% over the limit or 14 days past it, whichever comes first, nobody can add files to Drive or create new Docs, Sheets or Slides. Editing existing files belonging to an over-quota user is blocked too.
Either way it's disruptive, and on Microsoft 365 a client emailing you will simply bounce. Keep an eye on usage and deal with it before it gets there.
How to manage storage
Clean up your inbox
The biggest space users are usually:
- Large attachments — search for emails with attachments over 5 MB
- Old newsletters and marketing emails — unsubscribe and delete
- Spam and junk folders — empty them regularly
- Sent items — these count toward your storage too
In Gmail, search for has:attachment larger:5M to find emails with attachments over 5 MB.
Archive to tidy up — but not to save space
Archiving removes emails from your inbox (so you don't see them every day) but keeps them searchable. In Gmail they move to the All mail label, and if someone replies the message comes back to your inbox.
To archive in Gmail, tick the box next to a message and click Archive at the top. The keyboard shortcut is E, but shortcuts have to be turned on first in Gmail's settings. In Outlook, use Archive.
One thing to be clear about: archiving is for tidiness, not for space. The messages are still in your account, so they still count toward your storage. To actually reclaim space you have to delete things and empty the trash.
Empty the trash
In Gmail, a deleted message sits in Trash for 30 days and is then permanently deleted; you can recover it at any point before that. Messages in Trash and Spam still count toward your storage, so emptying them is one of the quickest ways to free space.
Microsoft 365 works differently. By default there is no time limit on how long items sit in your Deleted Items folder, and they count toward your mailbox quota until you empty it. Once you remove something from Deleted Items it stays recoverable for a further 14 days by default, which an admin can raise to a maximum of 30.
Upgrade your storage
If your team genuinely needs more space, upgrading to a higher plan is usually the simplest solution.
- In Google Workspace, moving to an edition with a bigger per-user figure increases the pooled storage available to everyone, and extra storage can be added separately. Check the figure before you move — a more expensive edition doesn't automatically come with more storage
- In Microsoft 365, your plan sets the maximum mailbox size. An admin can set a user's limit lower than that and raise it again up to the maximum, but not past it. For old mail there's the archive mailbox instead — a separate mailbox with its own quota, 50 GB on Business Basic and Business Standard, with Exchange Online Archiving sold as an add-on when that isn't enough
Ask us and we'll work out which of those actually solves your problem — they aren't interchangeable.
Email archiving for compliance
Some industries and jurisdictions require businesses to retain email records for a specific number of years. This is different from general storage management — it's a legal requirement.
Both Google Workspace and Microsoft 365 offer archiving features for compliance:
- Google Vault: retains email, applies legal holds, and lets you search it for legal and compliance purposes. It is included with Business Plus, Enterprise Standard and Enterprise Plus — not with Business Starter or Business Standard, so check which edition you're on before you rely on it
- Microsoft 365: Exchange Online Archiving for the archive mailbox itself, and Microsoft Purview (the current name for Microsoft's compliance tooling) for retention policies, legal holds and eDiscovery
Check your compliance requirements
If you work in a regulated industry (legal, healthcare, finance, public sector), speak with your compliance advisor about email retention requirements before setting up your archiving policy.
Shared mailboxes and storage
A shared mailbox in Microsoft 365 has its own storage quota, separate from anyone's personal mailbox. Without a licence of its own it's limited to 50 GB; assigning it an Exchange Online Plan 2 licence raises that to 100 GB. Google Workspace handles shared addresses through Groups instead, which works differently — ask us if you need to know how your particular setup counts.
Common questions
How do I check how much storage I'm using in Gmail?
Because Google Workspace pools storage, there are two views. As a user, open Google Drive and click Storage in the left-hand menu — your files list largest first. As an admin, go to Menu → Storage in the Google Admin console for the whole organization's usage and a breakdown by Drive, Photos and Gmail, plus a list of the users taking up the most space. Admin console figures can lag by up to 24 hours; Google says the organization-wide storage bar near the bottom of the Drive storage page updates within 4 hours instead.
How do I check storage in Outlook / Microsoft 365?
In Outlook on the web, go to Settings → Account → Storage. In new Outlook for Windows it's Settings → Accounts → Storage. Either way you get a breakdown of how much space each folder is using, and the option to permanently delete everything in a folder — or just items older than 3, 6 or 12 months.
Should I download and delete old attachments to save space?
You can — but make sure you have a reliable local backup before deleting anything important. Losing an email attachment is often irreversible. A simpler approach is to upgrade storage or move old files to Drive/OneDrive.
Does my email take up space even when I read it on my phone?
Your phone displays a copy of what's on the server. The emails are stored on the server — your phone doesn't change your storage usage significantly.
Related guides
- Email security basics
- Storage & quotas in Google Workspace
- Storage & quotas in Microsoft 365
- Email not sending or receiving?
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