📡 Bandwidth Calculator
Monthly bandwidth usage for any website
About this calculator
Bandwidth math converts between speed, time, and data so you can plan transfers, streams, and hosting. Enter any two of transfer speed, duration, and data size and the calculator solves for the third — with bits, bytes, megabits, and gigabytes kept straight automatically.
Data equals speed × time, with 8 bits to a byte. A 100 Mbps connection moves 12.5 megabytes per second, so a 5 GB file takes about 7 minutes in theory — real-world overhead and congestion add 10 to 30 percent.
Tip: ISPs advertise megabits while devices report megabytes — divide the advertised speed by 8 before comparing it to your download progress, or every plan looks eight times slower than promised.