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Transfer Time Calculator
Work out how long moving a given volume of data takes over a given link, with realistic protocol overhead and sustained-throughput derating. Compares link speeds side by side so you can see what upgrading actually buys you.
Protocol overhead plus the gap between line rate and sustained speed.
6h 20mTransfer window22,857 seconds
87.5 MB/sEffective throughput700 Mbps of 1,000 Mbps line rate
2.00 TBPayload1.82 TiB
70%Derate applied
6.3 hHours
0.26 dDays
Same payloadAcross link speeds
| Link | Effective | Window |
|---|---|---|
| 100 Mbps | 8.8 MB/s | 2d 15h |
| 1 Gbps | 87.5 MB/s | 6h 20m |
| 2.5 Gbps | 218.8 MB/s | 2h 32m |
| 10 Gbps | 875 MB/s | 38m 6s |
| 25 Gbps | 2187.5 MB/s | 15m 14s |
| 40 Gbps | 3500 MB/s | 9m 31s |
| 100 Gbps | 8750 MB/s | 3m 49s |
Click a row to set that link speed above.
Method & assumptions
- Link speeds are decimal bits: 1 Gbps = 109 bits/s. Data volumes in GB/TB are decimal bytes; TiB is binary. Mixing the two is the usual source of a wrong answer.
- The derate covers TCP/IP and protocol overhead plus the gap between line rate and sustained throughput. 70% is fair for large files on a healthy LAN.
- Many small files are dominated by per-file round trips, not bandwidth — 30% or lower is realistic, and no link upgrade fixes it.
- The figure assumes the bottleneck is the link. If source disks, target disks, or a single-threaded copy are slower, they set the ceiling instead.
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Anyone planning a data migration, backup seed, or overnight cutover window.