WordPress backup space estimator

Estimate the storage for repeated full backup copies of one site from sizes you measure and an explicit compression assumption. WordPress documentation describes site backups as needing both files and the database; this worksheet adds those entered sizes for each modeled copy.

Enter all four values and calculate.

How the estimate works

• Uncompressed size per copy: files + database export.
• Estimated stored size per copy: uncompressed size × entered compressed-size percentage ÷ 100.
• Estimated total: stored size per copy × number of copies.

For example, a 2 GB files input and 0.5 GB database input make a 2.5 GB uncompressed backup set. If your measured or documented compression assumption is 80%, the modeled copy is 2 GB before multiplying by the number of copies. This is an arithmetic example, not a typical compression result.

Scope and limits

This is a capacity estimate, not a backup plan or a guarantee that a backup can be restored. It assumes every copy contains the same full files and database set and uses the same compression ratio. It does not model incremental backups, changing site size, archive overhead, temporary working space, provider retention rules, or additional copies made by backup software.

Measure the files and database export you actually intend to back up. WordPress documentation explains that typical site files and the database are separate parts of a full backup. Confirm whether your backup process includes uploads, configuration, generated variants, logs, or other data, and test restores. A storage total does not say whether copies are independent or stored in different locations.

Units are decimal: 1 GB = 1,000 MB. NIST describes SI prefixes; providers may display capacity differently, so convert units before comparing the result with an account limit.

Sources

• WordPress Developer Resources: Backups — explains that a typical full site backup includes both files and database, and discusses keeping copies in different locations; updated October 28, 2026, checked November 3, 2026.
• NIST Guide to the SI, Chapter 4 — decimal SI prefixes; checked November 3, 2026.

For a schedule that includes incremental copies, use the backup retention calculator. For measured site storage inputs, see the WordPress resource needs estimator and image storage planner. For steps to plan a host move, use the hosting move checklist.