Backup storage & duration calculator
Estimate retained capacity and transfer windows for a rolling full-and-incremental backup schedule.
Simple rolling planning model; excludes deduplication beyond the entered ratio, synthetic fulls, pruning lag, verification, restore time, growth and vendor behavior.
Included
- Every visible input and selected unit
- Reconciled intermediate values and result breakdown
- Reproducible URL state
Not included
- Simple rolling planning model; excludes deduplication beyond the entered ratio, synthetic fulls, pruning lag, verification, restore time, growth and vendor behavior.
What this means
Estimate retained capacity and transfer windows for a rolling full-and-incremental backup schedule.
Simple rolling planning model; excludes deduplication beyond the entered ratio, synthetic fulls, pruning lag, verification, restore time, growth and vendor behavior.
Intermediate values are not rounded; only the localized display formats the result.
Formula & worked example
retained bytes = (fulls × dataset + incrementals × changed bytes) × ratio × copies
2 TiB dataset, 5% daily change, weekly fulls and 30 restore points
- Inputs
- 5 fulls × 2 TiB + 25 incrementals × 0.1 TiB
- Calculation
- (10 TiB + 2.5 TiB) × 100% × 1 copy = 12.5 TiB
The modeled retained set is 12.5 TiB, averaging about 0.417 TiB per restore-point day.
How this calculation works
The calculation follows the formulas, definitions and assumptions explained on this page. The references below support the method and any stated boundaries.
Official sources
- NIST SP 800-209 — Security Guidelines for Storage Infrastructure — Public definitions and technical semantics used by this calculation