NAS and file transfers
Network speed calculator
Translate 1, 2.5, 5, or 10 GbE into practical throughput and an understandable transfer-time estimate.
Your inputs
Calculated result
293.75 MB/s practical
At 94% link efficiency, a 100 GB transfer takes approximately 5 min 40 sec. Storage speed, protocol overhead, and file count can reduce real performance.
Link rate
2.5 GbE
Theoretical
312.5 MB/s
Transfer time
5 min 40 sec
How to use this result
- • Eight network megabits equal one theoretical megabyte per second.
- • The default 94% efficiency accounts for ordinary protocol overhead, not slow storage.
- • Many small files can transfer much more slowly than one large sequential file.
How the calculation works
- Divide the link rate in megabits per second by 8 to get the theoretical megabytes per second.
- Multiply by an efficiency factor (94% by default) to account for Ethernet and TCP/IP protocol overhead.
- Divide the file size by the practical rate to estimate transfer time. Storage speed is not included.
Worked example
Copying 100 GB to a NAS at different link speeds
- 1 GbE: about 118 MB/s, 14 min 11 s
- 2.5 GbE: about 294 MB/s, 5 min 40 s
- 5 GbE: about 588 MB/s, 2 min 50 s
- 10 GbE: about 1,175 MB/s, 1 min 25 s
Each step up in link speed shortens a large sequential transfer proportionally, provided the storage on both ends can keep up.
Common questions
Why is my 1 GbE transfer around 110–118 MB/s instead of 125 MB/s?
125 MB/s is the theoretical maximum of a 1,000 Mbps link. Ethernet framing and TCP/IP headers consume part of it, so roughly 94% is achievable in practice.
Will 10 GbE make my NAS ten times faster?
Only if the storage can sustain it. A single hard drive typically manages a few hundred MB/s at best, so 2.5 GbE or 5 GbE may already match an HDD-based NAS; SSD arrays benefit most from 10 GbE.
Why are many small files slower?
Each file adds per-file protocol and filesystem overhead, so thousands of small files transfer far below the link's sequential rate.