Transfer time = File size (bits) ÷ Speed (bps). Remember: 1 byte = 8 bits.
1 GB file at 100 Mbps = (8,000 Mb) ÷ 100 = 80 seconds download time.
ISP speeds are in Mbps (megabits) — file sizes are in MB/GB (megabytes). Divide by 8 to convert.
This calculator is most useful when precision matters: technical specifications, recipe scaling, scientific measurements, or any context where an approximate conversion introduces real risk.
Many unit conversion errors arise from treating multiples incorrectly. Converting millimetres to kilometres, for example, requires two separate steps (mm → m, m → km), not a single division by 100.
A cyclist travelling internationally needs to calibrate their bike computer from miles to kilometres. A single precise conversion ensures the display is accurate for the entire trip — the difference between 60 miles and 96.6 km matters when tracking training load.
ISP speeds are in bits/sec. Files are in bytes. 100 Mbps = 12.5 MB/s. Also factor in server speed and Wi-Fi overhead.