How to estimate cloud backup storage cost

Estimate the backup set before choosing a plan

The source folder is not the same as the complete retained backup set. Add full backups, incremental changes, independent copies, and version history. Compression and deduplication can reduce the amount stored, but their effect should come from measurements of your own data.

For an illustrative workload, start with 1,000 decimal GB of source data. Retain one full backup and 30 incremental backups, each containing 5 percent of the source. Before compression, the retained set is 1,000 × (1 + 30 × 0.05), or 2,500 GB. Two independent copies make that 5,000 GB. This assumes each incremental stores the stated fraction; synthetic full backups and deduplication can behave differently.

Use average monthly capacity

Storage charges commonly follow data retained over time. A full backup added at the end of the month is not necessarily billed like a copy retained for the entire month. Keep a monthly capacity history and estimate your planning horizon. Include retained versions, failed-upload remnants, and any billable metadata your provider counts.

The Backup Storage Calculator makes its assumptions explicit. Feed the resulting capacity into the comparison desk, then add an ordinary month of downloads and read/write operations. To estimate a restore, run a second scenario with the complete backup set downloaded.

Check what happens when backups expire

A retention policy in your backup software can conflict with the provider's minimum storage duration. If an object expires early, a deleted-storage or early-deletion charge can remain. Minimum monthly capacity is another independent rule. Neither should be confused with the number of copies your software retains.

Our comparison applies the entered minimum capacity and known allowances, but does not infer object deletion history. For an archive class, also ask about retrieval charges and restore delay. Choose a recovery process that meets your recovery window, then price it.

Validate the estimate against a real bill

Run a representative backup and restore test. Record stored bytes, request categories, downloaded bytes, elapsed time, and the billed amount. Compare that invoice with your estimate and document the difference before expanding the deployment.

Account-wide free quotas, negotiated rates, taxes, support, and cross-region replication can change the final bill. Revisit the calculation after the first complete billing cycle and whenever your backup or retention policy changes.