How Confluence bills storage
The billing model behind your Confluence Cloud storage quota, and the five consequences that follow from it.
Your Confluence Cloud storage bill comes from one rule:
The bill is the sum of
fileSizeacross all versions of all active attachment objects.
Everything below follows from that sentence. Each point was checked against a live Confluence site rather than inferred from documentation.
Only attachments count
Page text, comments, page version history, whiteboards and databases are billed as zero bytes. Only attachment objects consume quota.
The practical consequence is the one most people get wrong: deleting pages does not reduce your bill, unless those pages carried attachments. A site with 100,000 pages and few attachments uses almost no quota.
Every version counts, forever
Confluence keeps every version of an attachment and bills each one at its full size. There is no sliding window and no upper bound.
A 40 MB presentation re-uploaded thirty times is billed as roughly 1.2 GB. The attachment list shows you one file of 40 MB.
This is where the space goes
On most sites, superseded versions are the largest single category of billed storage — and the only one that is invisible in the product.
Per object, not per blob
Two attachments with byte-identical content are billed twice. Confluence bills attachment objects, not distinct blobs of data.
So copying a page copies its storage cost, and the same PDF attached to twelve pages costs twelve times its size.
The trash is free
Content in the trash is billed as zero bytes. Purging the trash therefore does not change what you pay.
This matters because emptying the trash is the first thing most people try. It is the one cleanup step with no effect on the bill. Storage Optimizer does not suggest it.
Decimal units, byte-exact
Quotas are counted in decimal units: one KB is 1000 bytes, one GB is 1,000,000,000 bytes. Tools that use binary units (1 KiB = 1024 bytes) will report a smaller number for the same data — about 7% lower at gigabyte scale.
If a third-party figure disagrees with Atlassian's by roughly that margin, this is usually why.
What this means for cleaning up
Ranked by effect on the bill:
- Remove old attachment versions. Large, invisible, and safe to remove — the current version stays.
- Remove attachments nobody references. Files that no page embeds or links to.
- Deduplicate copied attachments. Same content attached in several places.
Emptying the trash, archiving spaces and deleting pages do not appear on that list, because they do not change the number.