The SharePoint admin centre shows total storage per site collection, but gives you no tenant-wide ranking view that lets you immediately see which sites are your biggest consumers. Here are four ways to generate that report, from free and built-in to automated and exportable.
| Method | Effort | Granularity | Sortable? | Exportable? | Best for |
|---|---|---|---|---|---|
| SharePoint admin centre | Low | Site collection | Yes (in UI) | Yes (CSV) | Quick spot-check, small tenants |
| PowerShell (Get-SPOSite) | Medium | Site collection | Yes (scripted) | Yes (CSV/Excel) | Automation, bulk data, scheduled runs |
| M365 Usage Analytics | Low | Tenant aggregate | Limited | Via Power BI | Executive summaries, trend reports |
| Report Master (ShareMaster) | Low | Site + library level | Yes (Excel) | Yes (Excel) | Per-library breakdown, no scripting |
Option 1: SharePoint Admin Centre
The Active sites list in the SharePoint admin centre includes a Storage used column. Clicking the column header sorts all sites by consumption, ranking them from highest to lowest. For tenants with fewer than a few hundred sites and no need for ongoing export, this is the fastest starting point.
The limitations are real. The admin centre shows storage at the site collection level and cannot break that total down by document library. If a site shows 80 GB, the admin centre cannot tell you whether that comes from one oversized library or dozens of smaller ones. You also cannot filter by site template, owner, or last activity, which limits how actionable the view is when you need to contact site owners about cleanup.
The admin centre does support a CSV export via the Export button. It includes the URL, site name, owner, storage used in megabytes, and storage limit. For a point-in-time snapshot this is sufficient. Tracking storage growth over months requires you to save those exports manually and align them yourself.
Option 2: PowerShell (Get-SPOSite)
The SharePoint Online Management Shell's Get-SPOSite cmdlet retrieves detailed metadata for every site collection in the tenant, including storage figures. A basic query to list all sites ranked by storage looks like this:
Get-SPOSite -Limit All | Select-Object Url, Title, StorageUsageCurrent, Owner | Sort-Object StorageUsageCurrent -Descending | Export-Csv -Path "C:\Reports\sp-storage.csv" -NoTypeInformation
The StorageUsageCurrent property returns storage in megabytes. Piping to Sort-Object and then Export-Csv gives you a ranked, importable file without the admin centre UI. You can schedule this script to run monthly and store the results for trend comparison.
For library-level detail within a site, PnP PowerShell's Get-PnPList can pull size information per list or library. Doing this across a large tenant requires connecting to each site collection in turn, which adds scripting complexity and runtime. A looping script is achievable but takes time to write, test, and maintain as the tenant grows.
PowerShell suits teams comfortable with scripting who want scheduled or automated reporting, or who need storage data combined with other properties (last activity date, template type, primary site owner). It requires a SharePoint Administrator or Global Administrator account and the SharePoint Online Management Shell module.
Option 3: Microsoft 365 Usage Analytics
The Microsoft 365 Usage Analytics report, available from the Microsoft 365 admin centre under Reports, provides a tenant-level view of SharePoint storage trends. It shows total storage consumed across the tenant, growth trends over time, and per-user activity metrics. It connects to Power BI for visualisation.
This is the weakest option for site-level storage investigation. Usage Analytics is designed for executive summaries and trend analysis, not for finding which individual sites are the biggest consumers. It does not expose per-site storage in a sortable format. Its strength is in trend direction: is total SharePoint storage growing month on month, and at what rate? For site-level cleanup work, it tells you almost nothing actionable.
Use it alongside, not instead of, one of the other methods when you need actual site rankings.
Option 4: Report Master (ShareMaster)
ShareMaster's Report Master exports a storage utilisation report for any selected site directly to Excel - the only method here that delivers library-level detail without custom PowerShell. The export breaks down storage consumed per document library, version count per library, and total site storage.
For storage cleanup projects, that detail matters. Knowing a site uses 62 GB total is less useful than knowing 48 GB of it sits in the Shared Documents library and version history accounts for most of that figure. With that detail, you know exactly where to focus the cleanup work rather than guessing or running a separate investigative step.
The Excel output makes it straightforward to share results with site owners. Owners can see which of their libraries are using the most storage, and the version count column immediately highlights where automatic versioning has produced bloat without anyone noticing. The output is also a natural input to a version trim operation: once you identify the libraries with the highest version counts, you can run the Version Trimmer on those libraries specifically.
See what Report Master exports and how to use the results to plan and prioritise your storage cleanup.
Decision Matrix: Which Method Fits Your Situation?
| Situation | Recommended method |
|---|---|
| Quick spot-check, under 50 sites, no export needed | SharePoint admin centre |
| Export needed, site collection level only, no scripting | SharePoint admin centre CSV export |
| Scheduled monthly reporting, combined with other site properties | PowerShell (automated with Get-SPOSite) |
| Executive storage trend report for leadership | M365 Usage Analytics |
| Library-level breakdown, no scripting, ready to take cleanup action | Report Master |
| Pre-migration storage audit across many sites | Report Master (per-site libraries) or PowerShell (site-level) |
| Identifying which libraries have excessive version counts | Report Master |
Frequently Asked Questions
How do I find out which SharePoint sites are using the most storage?
The SharePoint admin centre shows storage per site collection in the Active sites list, which you can sort by the Storage used column. For a full export or library-level breakdown, PowerShell's Get-SPOSite cmdlet or ShareMaster's Report Master provide more detail and exportable output without navigating the UI.
Can I see storage by document library rather than by site in SharePoint?
The native SharePoint admin centre shows storage at the site collection level only. For library-level detail, you need PowerShell with PnP or a third-party tool. ShareMaster's Report Master exports a per-library storage summary to Excel for each selected site, without any scripting.
Does SharePoint version history count toward storage quota?
Yes. Every version of a file stored in SharePoint Online consumes storage quota. In tenants with no version limit set, version history commonly accounts for 40 to 70 percent of a document library's total storage. ShareMaster's Version Trimmer is one of the fastest ways to recover quota without deleting any current file content.
Once you know which sites are consuming the most storage, the guide to reducing SharePoint storage fast walks through the order of cleanup steps that recovers the most quota in the least time.