A bandwidth calculator computes the time required to transfer a file over a network connection based on file size and connection speed.
About this calculator
A bandwidth calculator computes the time required to transfer a file over a network connection based on file size and connection speed. It also shows the difference between megabits per second (Mbps), the unit ISPs advertise, and megabytes (MB), which are used for file sizes. That 8-to-1 difference causes a lot of confusion.
Note: 1 byte = 8 bits, so a 100 Mbps connection transfers 12.5 MB per second, not 100 MB per second.
Common uses
- Estimate download time for a large file at your internet speed
- Calculate upload time for video files to a cloud service
- Understand why advertised speeds differ from actual transfer speeds
- Determine bandwidth required for a specific transfer time target
Frequently asked questions
Why are file sizes in MB but speeds in Mbps?
File sizes use bytes (B) while network speeds use bits (b), lowercase vs uppercase matters. 1 byte = 8 bits. A 50 MB file = 400 megabits (Mb). At 100 Mbps, transfer time = 400 Mb / 100 Mbps = 4 seconds. Always multiply file size by 8 before dividing by speed in Mbps.