Data Bandwidth Calculator
How it works
The file size in MB is first converted to megabits by multiplying by 8 (there are 8 bits in a byte), so it shares a unit with the connection speed. Dividing that megabit figure by the speed in Mbps gives the download time in seconds, which is then broken into hours, minutes and seconds for readability.
Nothing here accounts for protocol overhead, other traffic on the network, or a connection running below its rated speed — it is the theoretical best case, not a guarantee.
Frequently asked questions
Why megabits instead of megabytes?
Internet speeds are almost always advertised in Mbps — megaBITS per second — while file sizes are almost always shown in MB — megaBYTES. A byte is eight bits, so a file size has to be multiplied by 8 before it can be divided by a speed in Mbps; skipping that step silently answers a different question and understates the download time by a factor of eight.
Why is my real download usually a bit slower than this?
This is a best-case theoretical figure: it assumes every one of those megabits is spent carrying the file, with nothing held back for protocol overhead, and a connection speed that never dips below its rated number. Real transfers lose some throughput to both, so the actual time is typically a little longer than the estimate here, not shorter.
My Wi-Fi seems slower than my plan’s rated speed — why?
Wi-Fi has its own overhead and shares airtime with every other device on the network, plus distance from the router and interference both cut into throughput. The number on your internet plan is the wired maximum into your home, not a guarantee of what any one Wi-Fi device will see — a wired connection, or running a speed test on the device itself, gives a more accurate number to enter here.