Mbps vs MB/s: Bits, Bytes and Actual Download Rates
Mbps means megabits per second. MB/s, sometimes written MBps, means megabytes per second. The capital B matters: one byte contains eight bits, so divide Mbps by eight to get decimal MB/s. A 100 Mbps connection has a theoretical maximum of 12.5 MB/s.
Read lowercase b and uppercase B carefully
A bit is a binary digit; a byte contains eight bits. ISP connection rates usually use bits per second, while file transfer apps often display bytes per second. That difference in measurement does not mean the provider has reduced the speed by a factor of eight.
Use MB/s when discussing megabytes per second to avoid confusing capitalization. A speed is a rate, while GB is an amount of data. Converting Mbps directly into GB needs a duration as well as the rate.
Account for decimal and binary units
One decimal megabyte is 1,000,000 bytes. One mebibyte, written MiB, is 1,048,576 bytes. Therefore 100 Mbps is about 11.92 MiB/s even before network overhead. A lower number in MiB/s can represent the same data rate as a higher number in MB/s.
The same distinction applies to file sizes. A decimal 10 GB file contains 10,000,000,000 bytes, while 10 GiB contains 10,737,418,240 bytes. Use the unit stated by the application when estimating transfer time.
Turn a rate into a download estimate
At an ideal 100 Mbps, a decimal 10 GB file takes 800 seconds: 10,000 MB divided by 12.5 MB/s. That is 13 minutes 20 seconds. At an assumed 90% throughput, the estimate becomes about 14 minutes 49 seconds.
If a launcher is already reporting your sustained MB/s rate, divide the remaining megabytes by that rate. The observed rate already includes the effects of the connection and server; applying another 90% allowance would count the reduction twice.
| Mbps | Ideal MB/s | MB/s at an assumed 90% |
|---|---|---|
| 25 | 3.125 | 2.8125 |
| 50 | 6.25 | 5.625 |
| 100 | 12.5 | 11.25 |
| 300 | 37.5 | 33.75 |
| 500 | 62.5 | 56.25 |
| 1000 | 125 | 112.5 |
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Common questions
Is MBps the same as Mbps?
No. With standard capitalization, MBps is megabytes per second and Mbps is megabits per second. One MBps equals eight Mbps.
Is 1 Gbps equal to 1 GB/s?
No. One Gbps is 1,000 Mbps, equivalent to 125 MB/s or 0.125 GB/s in decimal units before overhead.
Sources and calculation method
Transfer examples use decimal GB and Mbps unless specified. Efficiency and spare capacity are stated assumptions. Service requirements can change; verify the linked documentation before choosing a plan.
Prepared by Download Speed Calculator. Read our methodology or report a correction.