A SharePoint site showing 400 GB used tells you almost nothing about where to start. Without a per-library storage breakdown, every cleanup decision is guesswork: you are equally likely to spend an hour on a library that contributes 2 GB as one that holds 180 GB of accumulated version history.
This guide walks through how to generate a per-library storage report for SharePoint Online, interpret the results, and prioritise which libraries to act on first.
What does a per-library SharePoint storage report show?
A per-library storage report breaks a site collection's total quota consumption into individual rows, one per document library. Each row shows the total storage that library occupies, split into current file size and version history storage. That split is the key insight: a library's current files might occupy 8 GB while its version history consumes a further 65 GB. Without this breakdown, the 65 GB is invisible inside the site's total number and there is no obvious starting point for cleanup.
Why site-level totals are not enough
The SharePoint admin center shows total storage per site collection. That number includes current files, version history, recycle bin contents, and metadata. It does not separate these components or break them down by library. Inside a site, Site settings > Storage Metrics does break the total down by library and folder, but each figure still includes version history without showing how much of it is old versions, and it covers one site at a time. As a result, a site sitting at 95% of its quota could be in that state for very different reasons: a handful of large video files uploaded to a single library, version history spread across dozens of smaller libraries, or a recently emptied recycle bin that has not yet cleared from the quota counter.
Each of those situations calls for a different response. A site-level total sends you into each library manually to investigate. A per-library report with version history broken out takes you directly to the right library and tells you which cleanup action to apply.
How to generate a SharePoint storage report by library with ShareMaster
Step 1: Pick the report that matches your scope
Open ShareMaster and select Reports (the Report Master area). Two tiles do this job. Site Storage Metric covers every document library on one site you have access to. Tenant Storage Metric walks every unlocked site in the tenant, subsites included, and needs an account with the SharePoint Administrator role; where that account is not a site admin, ShareMaster adds it for the run and removes it afterwards.
For an initial audit, the tenant report surfaces the highest-impact libraries regardless of which site they live in. You can always narrow the scope to single sites once you know where to focus.
Step 2: Run the report
Connect and let it run. ShareMaster reads every file and every retained version in each document library to add up the sizes, so the time it takes depends on how many files and versions there are rather than how many sites. Start with one large site if you want a feel for the pace.
Step 3: Save the workbook
When the run finishes, save the Excel workbook. The Report Summary sheet has one row per library, sorted largest first. A second sheet lists the largest individual files with their total and current size, and the single-site report adds a sheet per library with every file and its versions.
See what Report Master exports
Step 4: Sort and prioritise
In Excel, sort the Amount saved if trimmed column from largest to smallest. The libraries at the top of that list are your primary targets: they hold the most accumulated historical data and will yield the largest storage reclaim per cleanup action. Cross-reference with the largest-files sheet: big files that are edited often, such as design files, images and video, build up version storage fastest.
Reading the results: what the columns mean
| Column | What it means | What to look for |
|---|---|---|
| Site URL and Library Name | Which site and document library the row describes | Filter to one site, or group by site to see which sites carry the most |
| Total Size (GB) | The library's files plus every retained version of them (recycle bin contents are not included) | Libraries over 10 GB are worth investigating; over 50 GB are immediate priorities |
| File Size (GB) | Storage consumed by the current version of each file only | The baseline: what the library would consume if version history were cleared entirely |
| Amount saved if trimmed (GB) | Total Size minus File Size: the space taken by version history | The ceiling on what trimming could reclaim in this library |
The report does not count files or versions per file. If you need version counts, the single-site report's per-library sheets list each file's versions, and Microsoft's version storage usage report (queued per site from SharePoint Online PowerShell) produces a CSV of every version. New libraries default to 500 major versions unless an organisation, site or library limit says otherwise.
What to do with high-storage libraries
Version history dominates: apply a version trim
When a library's version history is significantly larger than its current file size, a version trim is the correct first action. Use Space Master's Version Trimmer to set a keep policy for that library: for example, retain the last 20 versions per file and, optionally, only delete versions older than a date you choose. Run it with Execute Report first to see what would go. On a library where files carry around 200 versions each, keeping 20 removes roughly nine in ten versions, while the current version of every file is left alone.
For a detailed walkthrough of version trimming, see the guide to trimming SharePoint version history.
Current file size dominates: look at the files themselves
If a library's current file size is the dominant number rather than its version history, the storage is in the files themselves. This is where file-type matters: a library full of raw image files, uncompressed CAD exports, or large video files can legitimately consume hundreds of gigabytes in current content alone. Options here include moving large media to a dedicated storage location, using Space Master's Image Reducer to compress oversized images in-place, or archiving files that are no longer actively referenced.
Run before any migration
A per-library storage report run before a cross-tenant or same-tenant migration tells you the exact data volume you are migrating, separated by library. Libraries with large version history that you plan to migrate with full version preservation will dramatically inflate the migration data volume. Identifying them in advance lets you choose which libraries to trim first, reducing migration time and destination quota consumption from day one.
Frequently Asked Questions
Can the SharePoint admin center show storage broken down by library?
The SharePoint admin center shows total storage per site only. Inside each site, Site settings > Storage Metrics breaks the total down by library and folder, but its figures include version history without separating it out. Microsoft's version storage usage report (a PowerShell job per site) lists every version, and ShareMaster's Site Storage Metric and Tenant Storage Metric reports put total size, current file size and version history side by side for each library.
What is version history storage in a SharePoint library report?
Version history storage is the quota consumed by historical versions of files, separate from the current version's size. A library where current files total 10 GB but total library size is 85 GB has 75 GB in version history. Identifying this split is the prerequisite for targeted cleanup.
Which libraries should I target first when cleaning up SharePoint storage?
Prioritise libraries where version history storage is large relative to current file size. A ratio of 5:1 or higher indicates a library where a version trim will reclaim significant quota with minimal risk. Large files that are edited often, such as design files, images and video, build up version storage fastest, because each retained version adds to the library's total.
Does SharePoint storage include items in the recycle bin?
Yes. Deleted items keep counting toward the site's storage while they sit in the recycle bin. A per-library report does not include them, so if the site total is higher than the library totals explain, check the recycle bins. Emptying them releases the space without any action on the library's current files or version history, although the admin center's storage figures can take 24 to 48 hours to catch up.