Enter backup planning inputs
Example data table
| Scenario | Source Size | Changed Data | Link | Sustainable Throughput | Estimated Time | Window Status |
|---|---|---|---|---|---|---|
| Full backup | 12 TB | 100.00% | 10.00 Gbps | 2,048.00 MB/s | 1h 16m 43s | Within window |
| Incremental backup | 40 TB | 4.00% | 1.00 Gbps | 645.12 MB/s | 26m 21s | Within window |
| Differential backup | 18 TB | 3.00% | 750.00 MB/s | 1,755.00 MB/s | 21m 46s | Within window |
Formula used
This calculator estimates how much backup data must move and whether the available window can finish the job.
Logical Backup Size = Source Size × Selected Backup Scope
Optimized Size = Logical Backup Size × (1 − Compression Savings) × (1 − Deduplication Savings)
Transferred Size = Optimized Size × (1 + Protocol Overhead + Retry Overhead + Encryption Overhead)
Sustainable Throughput = Link Speed × Parallel Streams × Stream Efficiency
Estimated Duration = Transferred Size ÷ Sustainable Throughput
Required Throughput = Transferred Size ÷ Backup Window
Differential mode approximates cumulative changed data as change rate multiplied by days since the last full backup, capped at 100% of the source.
How to use this calculator
- Enter the protected source size and choose GB, TB, or PB.
- Select full, incremental, or differential backup behavior.
- Set changed data rate and days since full backup when needed.
- Add compression, deduplication, and overhead estimates from your environment.
- Enter link speed, stream count, and expected stream efficiency.
- Provide the allowed backup window in hours, then calculate.
- Review estimated duration, required throughput, and window utilization.
- Download the CSV or PDF summary for planning or reporting.
Frequently asked questions
1. What does this calculator measure?
It estimates sustainable backup throughput, total transferred data, completion time, and whether the backup fits inside the planned window.
2. Why is logical backup size different from transferred size?
Logical size reflects protected data scope. Transferred size also includes reductions from compression and deduplication, then adds network, retry, and encryption overhead.
3. When should I use incremental mode?
Use incremental mode when only changed data moves during each run. It is common for daily jobs that follow a separate full backup schedule.
4. How is differential mode estimated?
The calculator multiplies changed data rate by days since the last full backup. That approximates cumulative changed data and caps the value at the full dataset.
5. What is stream efficiency?
Stream efficiency represents real-world performance losses from protocol behavior, storage latency, software limits, CPU contention, and imperfect parallelism.
6. Should I enter advertised link speed?
Enter a realistic sustained value whenever possible. Advertised bandwidth alone often overstates actual backup throughput under mixed workloads and shared infrastructure.
7. Why are compression and deduplication separate?
They reduce data differently. Compression shrinks block contents, while deduplication removes repeated blocks or files across protected datasets and backup copies.
8. Can this help with capacity planning?
Yes. Use required throughput, recommended stream count, transferred size, and window utilization to compare infrastructure options and justify upgrades.