How the formula works
Time (seconds) = file size in bytes × 8 ÷ link speed in bits per second. MB and GB use decimal multiples; MiB and GiB use binary multiples.
Worked example
10 GB × 8 = 80 gigabits. At 100 Mbps (0.1 gigabits per second), the theoretical time is 800 seconds, or 13 minutes 20 seconds.
Limitations: The tool does not model TCP/IP headers, retries, Wi-Fi, latency, shared traffic, throttling or disk speed.