Convert between file size, connection speed and transfer time, in either direction.
The method behind this calculator
The confusion in every transfer estimate is bits versus bytes. Connection speeds are quoted in megabits per second while file sizes are in megabytes, and there are eight bits to a byte — so a 100 Mbps line moves about 12.5 MB each second, not 100.
Real throughput also falls short of the advertised figure because of protocol overhead, server limits and congestion. The efficiency setting accounts for that, and 85% is a reasonable default for a wired connection.
The default scenario, worked through
As an example, with a real-world efficiency of 85%, the calculator returns a transfer time of 40 min 9 s. Underneath, At full advertised speed comes out at 34 min 8 s and File size in megabits at 204,800 megabits. Change any field and every figure updates as you type.
How to use it
- Enter the file size and its unit.
- Enter your connection speed in Mbps, Gbps or MB/s.
- Adjust the efficiency figure if your connection runs better or worse.