Formula
Download time = file size in bits ÷ internet speed in bits per second
Because internet speed is usually shown in megabits per second, you need to convert the file size into bits first. Then divide by the speed.
Example
A 10 GB file is roughly 85.9 billion bits. At 100 Mbps, the perfect-case estimate is about 859 seconds, or roughly 14 minutes and 19 seconds.
Why reality is slower
- Network overhead reduces usable throughput.
- Wi‑Fi quality and interference reduce stability.
- The server may cap the transfer rate.
- Your device or storage can become the bottleneck.