SharePoint "Plan 2" is not unlimited: how the tenant pool is really sized, which licences add to it, and what eats it
Open the licence details of a Microsoft 365 E3 user and one of the service plans listed is SharePoint (Plan 2). Search for "SharePoint Plan 2 storage" and the first thing you find is a decade of forum threads about unlimited. Put the two together and you get the belief that a tenant on E3 or E5 cannot run out of SharePoint space. It can, it does, and the email that says so ("SharePoint Online is out of storage space. Sites are in read-only mode") arrives at exactly the wrong moment. This article is the arithmetic: how the pool is sized, which licences add to it and which add nothing, what draws on it, what happens at the line, and what the three ways out cost.
Where the confusion comes from
Two different products carry the words "Plan 2", and only one of them was ever "unlimited".
OneDrive for Business (Plan 2) was the per-user OneDrive SKU whose marketing said unlimited, and whose practice was 5 TB by default with support-ticket expansion to 25 TB. That is per user, it is OneDrive, and it is the subject of our earlier article on its retirement.
SharePoint (Plan 2) is the SharePoint service plan bundled into E3/E5 (Plan 1 is the one inside E1 and the Business plans). The difference between Plan 1 and Plan 2 is features, not capacity: both draw on the same organisation-wide pool, sized by the same formula. Plan 2 adds no storage. Microsoft's own service description now spells it out in a footnote that reads like it was written after too many support calls: "The total storage for your tenant isn't unlimited. It's the sum of the base storage allocation plus the additional storage provided by each user."
The standalone SharePoint Plan 1 and Plan 2 SKUs (bought on their own, not inside a suite) are also on their way out: no new purchases after 31 May 2026, no renewals after January 2027, end of service December 2029. If your tenant's pool is partly built on standalone SharePoint licences, that 10 GB per licence goes away at the renewal you cannot make.
The formula
For every commercial, non-education tenant the pool is:
"Purchased" is the word to notice. The pool counts licences you own, assigned or not; a tenant that owns 500 E3 and has assigned 420 still gets 5,000 GB from them. It also means the pool moves at renewal: cut 100 seats and the pool shrinks by 1,000 GB the same day, which is how a tenant with a comfortable 20% headroom ends up over the line after a headcount reduction without anyone uploading a byte.
Which licences add 10 GB, and which add nothing
| Licence | Adds to the pool | Note |
|---|---|---|
| Microsoft 365 Business Basic / Standard / Premium | 10 GB each | Teams Essentials also carries 10 GB per user |
| Microsoft 365 E3 / E5 (and A3/A5, G3/G5) | 10 GB each | The "Plan 2" tenants. Same 10 GB as everyone else |
| Office 365 E1 / E3 / E5 | 10 GB each | Plan 1 or Plan 2 inside; capacity identical |
| SharePoint Plan 1 / Plan 2 standalone | 10 GB each | Retiring: no new purchases after 31 May 2026, no renewals after January 2027 |
| Visio Plan 2, Project Plan 3 / 5 | ≈ 10 GB each | Learn says "approximately"; they also consume storage through their own files |
| Microsoft 365 F1 / F3, Office 365 F3 | 0 GB | A frontline-only tenant gets the 1 TB base and nothing more, however many seats |
| OneDrive standalone plans | 0.5 GB each | Not 10. Also retiring on the same timetable as SharePoint standalone |
| Dynamics 365 (Sales, CE, F&O) | 0 GB | Their entitlement is Dataverse storage; documents they push into SharePoint still consume the pool |
| Copilot, Exchange-only, Teams-only, add-ons | 0 GB | Not in Learn's table, and they contain no SharePoint service plan |
The frontline row is the one that causes the most surprise, so a worked example. A hypothetical tenant with 400 Microsoft 365 E3 and 600 Microsoft 365 F3 seats might expect 1 TB + 1,000 × 10 GB = 11 TB. What it actually has is 1 TB + 400 × 10 GB = 1,024 + 4,000 = 5,024 GB, just under 5 TB. The 600 frontline seats contribute nothing, and the storage bar in the SharePoint admin centre will say so. If your bar shows a number you cannot reconcile with your licence count, the Microsoft 365 admin centre has a diagnostic for exactly this ("SharePoint Online out of storage space" in the help pane) that shows how the quota was assembled.
What draws on the pool, and what doesn't
The second half of the confusion is on the consumption side: people are surprised by what counts and by what does not.
| Counts against the pool | Does not count |
|---|---|
| Every site's content: team sites, communication sites, Teams-connected sites, channel sites, hub sites, the root site, classic sites | OneDrive accounts (each user's OneDrive has its own per-user quota; a tenant can be over its pool with every OneDrive half empty, and vice versa) |
| Previous versions of every file (500 majors by default, each a full copy) | Exchange mailboxes and their archives |
| Both stages of every site recycle bin, for up to 93 days after deletion | Sites in the tenant recycle bin (deleted whole sites): Learn is explicit that these don't count toward the organisation's usage |
| The Preservation Hold library on any site under a retention policy or hold | Archived sites and files under Microsoft 365 Archive, while Archive is turned on and its billing is healthy (they count as archived storage, metered separately) |
| Teams meeting recordings saved to channel sites; documents Dynamics 365 or Power Platform write into SharePoint libraries | Site metadata (a separate 1,000 GB per-site allowance that is almost never reached) |
The four rows on the left are the four buckets of the read-only audit: visible files, versions, recycle bins, Preservation Hold. Versions and recycle bins are where a site becomes two or three times the size its file count suggests, and neither shows up when a site owner looks at the library. The Archive row is worth a second look: the moment Archive is turned off, or its pay-as-you-go billing lapses, every archived byte counts as active again, and a tenant that was under the line by virtue of archiving is over it.
One more counting rule: a single site is capped at 25 TB regardless of the pool. A site cannot borrow beyond that even if the tenant has room, and the manual site-limit field in the admin centre will accept 25,600 GB whether or not the organisation owns that much.
What happens at the line
Three things, in roughly this order.
- The warning. Global and SharePoint admins receive "There is not enough storage space on SharePoint Online", and a banner appears on the Active sites page. The storage-used figure that triggers it lags reality by 24 to 48 hours, so a cleanup done this morning will not move the bar until tomorrow or the day after.
- Site creation stops. Learn's storage-planning FAQ: once the quota is exceeded, classic site creation and site creation through PowerShell are blocked. Provisioning scripts start failing with no obviously related error.
- Read-only. "If your tenant continues to operate above your storage limits, you are at a risk of your environment being put into 'read-only' mode": users can open and read, and cannot add or modify, until usage drops or capacity is bought. The out-of-storage email's second form says exactly that: "Sites are in read-only mode and changes can't be saved."
Three ways out, and what each costs
All prices are Microsoft's public US list figures on Learn at the time of writing; check the admin centre for your agreement and currency.
| Option | Mechanism | Price on Learn | When it fits |
|---|---|---|---|
| Office 365 Extra File Storage | Add-on bought in 1 GB units, any quantity, added to the pool. Reducible to 1 GB later; removing it entirely needs a support ticket. Available to Business, E1–E5, F1/F3 and SharePoint Plan 1/2 tenants | Priced per GB per month in the admin centre at purchase; Learn does not print a list price | Predictable overage you want on the subscription invoice rather than a pay-as-you-go meter |
| Microsoft 365 SharePoint Storage (pay-as-you-go) | Azure-billed meter for every GB above the tenant quota. Commercial tenants only; not Education, GCC or 21Vianet | $0.20 per GB per month (shown on the invoice as $0.00667/GB/day) | Variable overage, or a bridge while you clean up: you pay for the overage that exists each day, not a fixed block |
| Microsoft 365 Archive | Cold sites and files are reclassified from active to archived storage and stop counting against the pool. Metered only when archived + active exceeds the quota | $0.05 per GB per month on the excess; no reactivation fee since 31 March 2025, but reactivated content cannot be re-archived for four months | Cold content you must keep (retention, legal, "just in case") that nobody opens: a quarter of the active rate |
| More licences | Each eligible seat adds 10 GB | The seat price | Almost never the cheap route: 10 GB per seat at any realistic seat price is far above $0.20/GB, unless the seat was needed anyway |
The fifth option is the one the other four exist to postpone: deleting or trimming what should not be there. On a typical over-quota tenant the first pass through versions, recycle bins and departed users' content recovers more than the overage, and it costs nothing but the audit. The version-trimming article covers the biggest bucket and the retention rules that decide whether a trim frees anything at all.
Reading your own tenant in five minutes
SharePoint Online Management Shell, SharePoint administrator, nothing written.
Connect-SPOService -Url https://TENANT-admin.sharepoint.com
# Pool: total and used, in MB
Get-SPOTenant | Select-Object StorageQuota, StorageQuotaAllocated
# Every site's current usage, largest first (OneDrive excluded)
Get-SPOSite -Limit All -IncludePersonalSite $false |
Sort-Object StorageUsageCurrent -Descending |
Select-Object Url, StorageUsageCurrent, StorageQuota, LockState -First 25Then reconcile StorageQuota against the licence table above: 1,024 GB plus 10 GB per eligible seat you own, plus any Extra File Storage. If they do not match, run the admin-centre diagnostic before you buy anything. If they do match and you are over, the site list tells you where to start, and the four buckets inside the top sites tell you how much of it is versions and bins rather than files anyone would miss.
Checklist
- Write down the pool formula for your tenant: 1,024 GB + 10 GB × (eligible seats owned) + add-on. Frontline seats are zero.
- Compare it with the storage bar. A mismatch is a support case, not a purchase.
- Before any renewal that changes seat count, recompute the pool and compare it with current usage plus 24–48 hours of lag.
- If you are over: audit first (versions, recycle bins, Preservation Hold, departed users), then Archive for the cold remainder, then the pay-as-you-go meter for what is left. Buy seats for storage last.
- If you rely on Archive to stay under the line, put its billing health on the monthly check: when Archive stops, archived storage becomes active storage.
Free: pool position, top sites and departed-user OneDrives in one run
StorageScout Lite is a read-only PowerShell audit that prints the pool formula against your actual quota, lists every site by size, and finds every departed-user OneDrive with its size. No server, nothing leaves your tenant. The paid tiers add the per-site version, recycle-bin and Preservation Hold breakdown, priced against the $0.20 meter and the $0.05 Archive rate, so you know what the cleanup is worth before you start it.
Download StorageScout Lite — free See what Solo addsDisclosure: StorageScout is our product. Prices are Microsoft's public US list prices as documented on Microsoft Learn at the time of writing; your agreement, region and currency may differ. The tenant example is hypothetical. StorageScout is independent and not affiliated with or endorsed by Microsoft.
Sources
- SharePoint limits (service description) — 1 TB + 10 GB per licence by plan family, F1/F3 at 1 TB, OneDrive standalone 0.5 GB, Visio/Project ≈ 10 GB, Dynamics 365, 25 TB per site, binary GB, "isn't unlimited" footnote, read-only risk
- Manage site storage limits — storage bar, 24–48 h lag, deleted sites in the tenant recycle bin excluded, automatic vs manual limits, 25,600 GB maximum
- SharePoint storage planning — quota FAQ, site creation blocked when over quota, the three purchase routes
- SharePoint Online out of storage space — the warning emails, read-only wording, the admin-centre diagnostic, archived data excluded from active quota
- Add more OneDrive and SharePoint storage — Extra File Storage in 1 GB increments, eligible plans, reduce-to-1-GB rule, pay-as-you-go SharePoint Storage
- Pay-as-you-go pricing — Storage services — $0.20/GB/month SharePoint Storage, $0.05/GB/month Archive, no reactivation fee
- Pricing model for Microsoft 365 Archive — metered only above quota, reactivation fee eliminated 31 March 2025, four-month re-archive restriction, archived content counts as active when Archive or billing is off
- Partner Center, January 2026: retirement of standalone SharePoint Online and OneDrive for Business plans — end of sale 31 May 2026, end of life January 2027, end of service December 2029
- Learn about retention for SharePoint and OneDrive — Preservation Hold library counts against site storage