Formula
T = (S × 8) ÷ (R × η)
Convert the file size to bytes and the rate to bits per second. Eight bits make one byte. Efficiency reduces the usable rate.
Network & data
● Runs locallyFile Transfer Time
Estimate how long an upload, download or local copy will take. CalcFlow converts decimal or binary file sizes and bit- or byte-based speeds to canonical units, then shows the ideal duration and the efficiency assumption behind it.
Example values
Estimated transfer time
Assumptions
- The selected rate is treated as sustained end-to-end throughput.
- Protocol, server, storage and Wi-Fi overhead can make real transfers slower.
Mbps means megabits per second; MB/s means megabytes per second. At the same prefix, 1 MB/s equals 8 Mbps.
Formula review
Formula v1.0.0
Reviewed 2026-08-03
CalcFlow engineering review
File Transfer Time: Worked example
A 4.7 GB file contains 4.7 billion bytes. At 100 Mbps and 100% efficiency: 4.7 × 10⁹ × 8 ÷ 100 × 10⁶ = 376 seconds, or 6 min 16 s.
Frequently asked questions
Why is my real transfer slower?
Advertised link speed is not always sustained throughput. Protocol overhead, congestion, Wi-Fi, disks and remote servers can all reduce the effective rate.
Is MB/s the same as Mbps?
No. MB/s uses bytes and Mbps uses bits. One byte is eight bits, so 100 Mbps is 12.5 MB/s before overhead.
Should I use GB or GiB?
Use GB for decimal vendor sizes and GiB when the value is explicitly binary. CalcFlow keeps the distinction visible.