How to Buy More SharePoint and OneDrive Storage
The classic route is the Office 365 Extra File Storage add-on, bought in the Microsoft 365 admin center in 1 GB increments at $0.20 per GB per month, which works out to $2,400 per terabyte per year. As of 2026 there are three other ways to add capacity, including two new pay-as-you-go services, and they suit different problems.
This guide covers all four options, what each actually costs, which subscriptions are eligible, and the question worth asking before you buy any of them: whether the content driving you over quota needs to be sitting in SharePoint at all.
Option 1: Office 365 Extra File Storage
The long-standing add-on, and the one most tenants use.
- Price: $0.20 per GB per month. Only a tenant admin can see the price in the Microsoft 365 admin center.
- Increments: bought in 1 GB steps, so you can size it precisely and adjust later. You can reduce it to as low as 1 GB, but removing the add-on entirely requires contacting Microsoft support.
- Where it applies: the tenant-wide SharePoint storage pool, which covers SharePoint sites and the Teams sites backed by them.
Eligible subscriptions. Microsoft lists Office 365 Extra File Storage as available for Microsoft 365 Business Basic, Business Standard and Business Premium; Microsoft 365 E3 and E5; Microsoft 365 F1 and F3; Microsoft 365 for the web with SharePoint Plan 1 or Plan 2; Office 365 Enterprise E1, E2, E3 and E5; Office 365 A3 and A5 (faculty); and SharePoint Online Plan 1 and Plan 2. It is also available for GCC, GCC High and DOD plans. If the add-on does not appear in your admin center, your plan is not eligible for it.
One catch that surprises people: if you bought your subscription through Volume Licensing or a Cloud Solution Provider, you cannot buy Office 365 Extra File Storage directly from Microsoft. You have to arrange it through your partner or reseller.
To buy it: in the Microsoft 365 admin center, go to Billing and then the Marketplace (or Add more products in Simplified view), select the Office 365 category, find Office 365 Extra File Storage, enter the number of gigabytes you want, and place the order. The exact path differs slightly depending on whether your billing account is a Microsoft Customer Agreement or a Microsoft Online Subscription Agreement.
Option 2: Microsoft 365 SharePoint Storage (Pay-As-You-Go)
New in 2026, and worth understanding before committing to the add-on. Microsoft 365 SharePoint Storage entered public preview in June 2026 for all commercial tenants, though it is not currently available for education, GCC, or Microsoft 365 operated by 21Vianet customers. Instead of buying a fixed block of storage, you pay for what you use above your quota, billed through Azure.
It requires an Azure subscription and resource group, and the Owner or Contributor role on both, because billing runs through Azure pay-as-you-go rather than your Microsoft 365 invoice.
The detail to read twice: while your tenant is enrolled, Microsoft documents that you stop receiving quota-related email notifications and admin-center banner warnings, because the tenant is treated as being within quota. The storage pressure does not go away. The warnings do, and the bill grows quietly instead. If you later disconnect while over quota, enforcement resumes immediately.
That trade is reasonable if you are deliberately choosing elastic storage. It is a problem if those notifications were the only thing telling you your estate was growing.
Option 3: OneDrive Extra Storage
For individual users rather than the tenant pool. OneDrive Extra Storage is sold as capacity packs in 100 GB, 500 GB, and 1 TB through 6 TB sizes, assigned to a licensed user like any other add-on licence.
Constraints worth knowing: a capacity pack cannot be split across multiple users, a single user's total storage cannot exceed 25 TB, and if you previously set a lower storage limit for that user, you have to raise it separately before they can use the new capacity.
Option 4: Microsoft 365 OneDrive Storage (Pay-As-You-Go)
The OneDrive equivalent of option 2, entering public preview in July 2026. Same model: an Azure subscription, pay-as-you-go billing for usage above the licensed quota, and a 25,600 GB per-user maximum. Only the usage above the licensed quota is billed.
What Buying Storage Actually Costs
The arithmetic is what decides this, so it is worth setting out plainly. At $0.20 per GB per month:
| Extra storage | Monthly | Annual |
|---|---|---|
| 1 TB | $200 | $2,400 |
| 5 TB | $1,000 | $12,000 |
| 10 TB | $2,000 | $24,000 |
| 50 TB | $10,000 | $120,000 |
That cost recurs, it grows as the estate grows, and it buys nothing except permission to keep storing content you already have. For what each plan includes before overage starts, see SharePoint Online pricing.
The comparison that matters: the same data in Azure Blob Storage costs roughly $0.0184 per GB per month on the Hot tier, about $0.01 on Cool, and around $0.002 on Archive. Cool tier is roughly a twentieth of the SharePoint overage rate for content nobody is actively editing.
Before You Buy: Is the Content Even Active?
Most tenants that hit their quota are not storing more active work than before. They are storing years of accumulated files nobody opens. Research consistently finds that around 68% of enterprise data is never accessed after it is created, which means the majority of what you are about to buy storage for is inactive.
Three checks are usually worth doing before raising a purchase order:
- Find where the storage actually went. The free SharePoint Storage Explorer breaks down consumption by site, library and file type across the tenant, and finding your largest SharePoint sites covers the admin-center and PowerShell methods.
- Check version history. Every version of every file counts against the quota in full. Trimming it is frequently the single biggest reclaim available - see SharePoint version history storage.
- Check the Preservation Hold Library. If retention policies are active, deleted content is being copied into a hidden library that keeps consuming quota. The Preservation Hold Library guide explains how to find and manage it.
The full sequence is in how to reduce SharePoint Online storage.
The Alternative: Archive Instead of Buying
If the content is inactive but has to be kept, archiving moves it out of the expensive pool without deleting anything.
Squirrel archives inactive SharePoint Online documents into Azure Blob Storage in your own subscription, on scheduled lifecycle policies you define by age, last access, file type, library or site. A stub stays in SharePoint with the original file name, so users still see the file and restore it in one click, immediately, with no rehydration wait and no restore fee from Squirrel. Version history, metadata and permissions come back intact, archived content stays visible to SharePoint Search and Microsoft Copilot through Nutshell AI summaries, and it runs alongside active Microsoft Purview retention policies.
The structural difference from buying storage: archived data sits in an Azure account you own, at Cool-tier rates, and it stays yours if you ever stop using Squirrel. Buying Extra File Storage rents more room inside Microsoft's pool at roughly twenty times the per-GB price, and that bill recurs indefinitely.
For a vendor-neutral way to evaluate this properly, including the questions to ask any archiving supplier, see the SharePoint archiving buyer's guide and checklist.
Before buying more, it is worth confirming what is actually consuming the allowance: Teams channel files draw on SharePoint storage, not OneDrive. See SharePoint vs OneDrive vs Teams.
Frequently Asked Questions
How much does Office 365 Extra File Storage cost?
$0.20 per GB per month, which works out to $200 per terabyte per month or $2,400 per terabyte per year. It is bought in 1 GB increments in the Microsoft 365 admin center, and only a tenant admin can see the price there.
Which plans can buy Office 365 Extra File Storage?
Microsoft 365 Business Basic, Standard and Premium; Microsoft 365 E3, E5, F1 and F3; Microsoft 365 for the web with SharePoint Plan 1 or 2; Office 365 Enterprise E1, E2, E3 and E5; Office 365 A3 and A5 faculty; and SharePoint Online Plan 1 and 2, plus GCC, GCC High and DOD plans. If it does not appear in your admin center, your plan is not eligible.
Can I buy extra storage if I bought Microsoft 365 through a reseller?
Not directly. If your subscription came through Volume Licensing or a Cloud Solution Provider, Microsoft does not let you buy Office 365 Extra File Storage yourself. You have to arrange it through your partner or reseller.
What is the difference between Extra File Storage and the new pay-as-you-go storage?
Office 365 Extra File Storage is a fixed add-on billed per GB on your Microsoft 365 invoice. Microsoft 365 SharePoint Storage and Microsoft 365 OneDrive Storage, both in public preview during 2026, are pay-as-you-go services billed through an Azure subscription for usage above your quota. Note that while pay-as-you-go is enabled, quota warning emails and admin-center banners stop appearing, because the tenant is treated as within quota.
How do I add storage to a single user's OneDrive?
Use OneDrive Extra Storage capacity packs, sold in 100 GB, 500 GB and 1 TB to 6 TB sizes and assigned to a licensed user. A pack cannot be split between users, and one user cannot exceed 25 TB in total.
Is it cheaper to buy more SharePoint storage or archive to Azure?
Archiving is dramatically cheaper for inactive content. SharePoint overage runs at $0.20 per GB per month, while Azure Blob Cool tier is around $0.01 per GB per month for the same data. The trade-off is that archived files sit behind a stub rather than in the library directly, which is why the restore experience is the thing to evaluate closely.
What happens when I hit the SharePoint storage limit?
Once the tenant pool is exhausted, users cannot upload new files or create new items in affected sites until storage is added or content is reclaimed. Microsoft sends quota warnings before that point, unless the tenant is enrolled in pay-as-you-go storage, in which case those warnings stop.
Related reading
- How to reduce SharePoint Online storage
- SharePoint Online pricing: plans, storage and real cost
- SharePoint vs Azure Blob Storage cost calculator
- SharePoint archiving buyer's guide and checklist
- SharePoint storage limit warning: avoiding overage charges
Work Out What You Would Actually Save
Before signing off a storage purchase order, run your numbers through the SharePoint vs Azure storage calculator, or see how Squirrel archives inactive content into your own Azure storage. Questions: sales@smikar.com.
Mark Smith co-founded SmiKar Software in 2015 and has spent the past decade helping organisations solve Microsoft 365 data management challenges. He works with the SmiKar team to build solutions for SharePoint archiving, storage optimisation, governance and compliance, supporting customers from growing businesses through to Fortune 500 enterprises.
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