Estimate how long a download or upload will take at your connection speed, allowing for real-world overhead.
How the download time calculator works
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.
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.
The formula
Worked example
The calculator opens with a real-world efficiency of 85%. On those figures the transfer time is 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.