The complete 2026 guide to Microsoft 365 storage pricing

Microsoft 365 storage pricing is quoted in Microsoft's licensing guide in a dozen separate places. This is the consolidated 2026 reference — every price point every admin needs, with the context around when each one actually applies.

What is included (the free portion)

Before anyone pays extra, Microsoft 365 includes a baseline pool of storage per workload:

• SharePoint: 1 TB base + 10 GB per licensed Microsoft 365 user.
• OneDrive for Business: 1 TB per user (Business plans) up to unlimited (eligible E3/E5 tenants, with support request).
• Exchange primary mailbox: 50 GB (Business Basic/Standard) or 100 GB (Business Premium, E3, E5).
• Exchange archive mailbox: 100 GB auto-expanding to 1.5 TB (E3/E5 and compatible plans).
• Teams chat storage: included in the above (chat files live in OneDrive, channel files live in SharePoint).

When you need more — the add-ons

When any of those meters tips over the included amount, the add-ons kick in:

• SharePoint additional storage: $0.20 per GB per month, billed on the Azure invoice as "Additional File Storage." That is $200 per TB per month, or $2,400 per TB per year at list.
• OneDrive additional storage (per-user): typically bundled with an upgrade to a higher plan rather than purchased separately. E3→E5 users already have 5 TB; above that, Microsoft support request.
• Exchange Online Archiving add-on: $3 per user per month, used to add archive capacity to Business Basic/Standard users (who otherwise do not have archive).
• Exchange Online Plan 2 (for shared mailboxes >50 GB): $8 per month per shared mailbox you want to raise above 50 GB.

Discounts most tenants never apply

• Enterprise Agreement (EA): typically 15-25% off list on storage add-ons, applied automatically if the tenant is under an EA.
• Cloud Solution Provider (CSP): CSP partners price storage add-ons separately; it is worth asking a partner for a quote even if you are direct-with-Microsoft today.
• Non-profit and education: Microsoft 365 for non-profits applies a 50% discount or more on most add-ons.
• Prepaid annual: paying annually rather than monthly typically saves 15%.

A worked example — the 500-user tenant

A tenant with 500 Microsoft 365 E3 users has:

• SharePoint included: 1 TB + (500 × 10 GB) = 6 TB.
• OneDrive included: 500 × 1 TB = 500 TB (per-user, not pooled — matters for compliance, not for a shared quota).
• Exchange primary included: 500 × 100 GB = 50 TB (per-user).
• Exchange archive included: up to 500 × 1.5 TB = 750 TB of auto-expand (unused on most tenants).

If the same tenant's actual SharePoint usage is 10 TB, the overage is 4 TB → 4 × $200/month = $800/month = $9,600/year on the Azure invoice at list, before any discount.

Reducing the bill without reducing capability

Three levers reduce the bill without touching user capability:

1. Reclaim what is already paid for — most tenants have 20-40% recoverable without any loss of function.
2. Enable auto-expanding archive on E3/E5 users with heavy mailboxes — the archive is free up to 1.5 TB per user and most tenants do not use it.
3. Cap SharePoint major-version history on large libraries — reduces storage growth without affecting the version safety net.

TSO quantifies each of the three for your tenant specifically. The free first scan tells you the exact dollar figure the "Additional File Storage" line could be — before you renew for another year.