Estimate how long a file transfer will take, given its size and your connection speed.
Speed is in bits/sec (Mbps/Gbps, as ISPs advertise); file size is in bytes (MB/GB/TB), converted internally.
File sizes are conventionally measured in bytes (MB, GB, TB), while ISPs and network speeds are advertised in bits per second (Mbps, Gbps). The calculator converts file size from bytes to bits internally before dividing by the speed.
This is a theoretical transfer time at your connection's full advertised speed. Real transfers are usually slower due to network overhead, server-side limits, Wi-Fi conditions, and other traffic sharing the same connection.
It recalculates the same file size's transfer time across several typical connection speeds (10 Mbps through 1 Gbps), so you can see how much faster the same download would be on a different plan.