Free tool
Bandwidth & Transfer Time Calculator
Convert between bits and bytes, work out how long a transfer takes at a given speed, and size a connection for a number of users.
Bits, bytes and the number on the invoice
Connection speeds are sold in bits per second and files are measured in bytes, and there are eight bits in a byte. That single factor is why a 100 Mbps line does not move a 100 MB file in one second, and why customers think they have been sold something slower than they ordered.
Protocol overhead, latency, disk speed and whatever else is using the line all take a share. Seventy five percent of the advertised rate is a realistic working figure for a healthy connection, and far less on congested or wireless links.
The per user figure divides the line evenly, which is the worst case. In practice usage is bursty, so a shared connection usually feels faster than the straight division suggests until everybody tries to use it at once.