How do I calculate MB/s & MiB/s?

See

1> Megabyte per second

A megabyte per second (MB/s or MBps) is a unit of data transfer rate equal to:

1,000,000 bytes per second,

2> Megabit per second

A megabit per second (Mbit/s, Mb/s, or Mbps) is a unit of data transfer rate equal to:

1,000,000 bits per second

3>Mebibyte per second

A mebibyte per second (MiB/s or MiBps) is a unit of data transfer rate equal to:

1,048,576 bytes per second, or

4>Mebibit per second

A mebibit per second (Mibit/s or Mib/s) is a unit of data transfer rate equal to:

1,048,576 bits per second or

If I transfer 1381530 bytes in 17797601 nanoseconds, what is the data rate in those two measures?

0.0776 bytes/ns.

First, careful:

I've recently discovered that MB/s is technically equivalent to 8000 million bits/s

I've never heard of this definition.

"MB/s" usually means "megabytes per second". This can be one of two definitions, depending on who you ask:

• 1 million bytes per second (8 million bits per second) (per the IEEE's definition)
• The more commonly seen definition of 1024 * 1024 (1048576) bytes per second (8388608 bits per second), seen commonly in many usages.

In some really, really rare cases, "MB/s" could mean "megabits per second", but megabits per second is usually abbreviated to "Mbps" or "Mbits/s". The context will most often clue you in on which is appropriate: wireless transmission speeds, ethernet cards, etc. are typically measured in megabits per second; file transfers over the internet are measured in megabytes (or mebibyte, see next paragraph) per second.

The IEEE has proposed that computers should follow the SI prefixes, and use "Kilobyte" to mean 10³ bytes, not 2¹⁰ bytes, which has been done historically. (And thus created all the confusion over which definition of a megabyte one is actually using.) However, in many contexts, 10³ makes little sense, so different "binary" prefixes were introduced, such as the "Kibibyte", which is abbreviated KiB and always means 1024 bytes. In your case, there is it "Mebibyte", or MiB (and when per second, MiB/s) and means 1024*1024 bytes.

See the Wikipedia article on the Megabyte for more info.

(For the conversions to bits/s, I've assumed 8 bits/byte.)