Convert Mbps to MB/s – real download speed calculator

A 100 Mbps connection downloads at most 12.5 MB/s. Mbps to MB/s conversion works with a single division: a byte has eight bits[1], so MB/s = Mbps ÷ 8. Your provider quotes the speed in megabits, while the download window counts megabytes, which is why the number you see there is roughly eight times smaller.

Here is that division for a few plan speeds. A 300 Mbps plan gives 37.5 MB/s, 500 Mbps gives 62.5 MB/s, and a 1 Gbps plan, which is 1,000 Mbps, gives 125 MB/s.

Chrome and Firefox show smaller numbers for the same connections. Both browsers divide the byte count by 1,024 twice and still label the result MB/s[2][3]. Below 100 they keep one decimal place, and from 100 up they show a whole number, so a 100 Mbps connection appears as 11.9 MB/s and a 1 Gbps connection as 119 MB/s. Pick Binary (1024) in the converter to get the same figure.

If you read a speed in megabytes and want it back in megabits, use the MB/s to Mbps converter.

A bit is a single 0 or 1, and a byte is a group of eight bits[1]. File sizes and disk space are measured in bytes, while connection speeds, network ports and speed test results are measured in bits. The bytes to bits converter shows how many bits any number of bytes holds.

Mbps, Mb/s and Mbit/s all mean megabits per second, a million bits every second. NIST notes that this is how every telecommunications engineer uses the unit[1]. The only thing that separates Mbps from MBps is the case of the letter b: lowercase b is a bit, uppercase B is a byte, so MB/s and MBps are megabytes per second, a unit eight times larger.

A “1 gig” plan is a gigabit plan: 1,000 Mbps, or 125 MB/s.

A megabyte in the SI system is one million bytes, while a mebibyte, written MiB, is 1,048,576 bytes[1]. The Unit standard switch lets you choose between the two.

Next to a file that is still downloading, Firefox shows the time left, how much has arrived and the speed in brackets, for example (35.8 MB/sec). Both the US and the UK English versions of the browser write the unit that way, with /sec after MB[4][5].

On a 300 Mbps plan that bracket reads 35.8 MB/sec, not the 37.5 MB/s you get from dividing by 8. To check a Firefox reading against your plan, type the plan speed into the field and choose Binary (1024), and the result will match the browser.