Computer & IT
Cloud Storage Capacity Calculator
Project retained cloud data through growth, compression, deduplication, protection copies, snapshot overhead, and free-space reserve across a planning horizon.
Protected storage forecast
Forecast raw growth, data reduction, protection copies, snapshot overhead, reserve, and monthly cost
The capacity chain preserves each multiplier so logical growth is not confused with physical protected storage or provisioned free space.Capacity horizon
Raw, reduced, protected, and provisioned storage through time
Four curves expose where growth, reduction efficiency, copy policy, snapshots, and reserve each change the physical footprint.Detailed calculation process
Apply reduction before protection, then preserve operational free space
General symbolic formulas
Rn = R₀(1 + g)ⁿLn = Rn c(1 − d)Pused = Ln k(1 + s)Pprov = Pused / (1 − r)Pfree = Pprov − PusedCost = Pprov × pCompression and dedupe reduce one logical copy. Protection and snapshot overhead expand physical use. Reserve is free provisioned space, so it is applied last.
Symbols and units
Worked substitution with current inputs
Forecast capacity checkpoints
| Month | Raw TB | Reduced TB | Protected used TB | Provisioned TB | Monthly cost |
|---|
Use steps
- Measure raw ingestion growth over a representative period.
- Use achieved compression and dedupe ratios.
- Enter the actual copy, snapshot, and reserve policies.
Examples
Archive tier: slow growth may still require high copy durability.
Backup-heavy data: snapshot churn can exceed the simple overhead allowance.
Limitations
The forecast assumes compounded growth and stable ratios. It excludes tiering, object overhead, erasure coding, minimum billing units, egress, API charges, replication lag, snapshot churn curves, and price changes.
Cloud-storage FAQ
Is a compression ratio below one?
Yes. A stored/raw ratio of 0.68 means compressed data uses 68% of raw size.
Why divide by one minus reserve?
If used storage may occupy only 80% of provisioned space, provisioned capacity is used capacity divided by 0.80.
Does copy count model erasure coding?
No. Enter an effective physical multiplier or build a dedicated erasure-code model.