Mbps to MB/s converter
Convert between megabits per second and megabytes per second, and see why a 100 Mbps connection downloads at about 12.5 MB/s.
100 Mbps = 12.5 MB/s
Windows would usually show this as 11.921 MiB/s, even though it labels it MB/s. That is why a download often looks slower than your speed test suggests.
The conversion
There are eight bits in a byte, so divide megabits per second by eight to get megabytes per second. A 100 Mbps connection moves about 12.5 MB/s. Going the other way, multiply by eight.
The lower-case “b” means bits and the upper-case “B” means bytes. Mbps and MBps look almost identical and mean things that differ by a factor of eight, which is why this trips so many people up.
Why your download manager still disagrees
Even after dividing by eight, the figure your computer shows may look low. Network speeds are decimal — one megabit is exactly 1,000,000 bits. File sizes on Windows are binary: what it calls a megabyte is actually 1,048,576 bytes, properly named a mebibyte (MiB).
The gap is about 4.9% at this scale, and roughly 7.4% at gigabyte scale. The converter above shows both figures so you can compare like with like.
Which number should you use?
For working out how long something will take, use megabytes per second and check whether your file size is quoted in decimal or binary units. The download time calculator handles both.