Upload Speed (And Download Speed)

Is my upload speed 0.25 Mbps or 0.03125 MBps or is it 32 kBps? I'm so confused!!

If these terms related to upload speed mess with your head, then you're not alone. Those numbers are all the same and a lot of people get confused about them. For our purposes, they indicate the upload and download speeds of our online backups. So, let's get a handle on those terms and take the mystery out, shall we?

What you need to pay attention to is the "B" and the "b". It's simple but it makes a big difference in the upload speed numbers.

By the way, when I say upload speeds, you can apply it download speeds too. It's just that we're talking about online backups here so I'll say upload speed a lot.

If you see a term like MbPS or Mb/S, that's technically wrong. Believe it or not, each letter has an upper case/lower case rule that goes with it. Here's the accepted convention for each letter:

• b = bit
• B = Byte
• k = kilo
• M = Mega
• p = per
• / = per
• s = second

The important letter for us is the "b" because it means something different than "B".

You see, one "B" is equal to eight "b"s. So, in computer language we say "Eight bits are equal to one Byte" and yes, we usually capitalize the B in Byte.

Now, you'll probably only see lower case letters for the "ps" or "/s" (not guaranteed) but you might see upper case or lower case "M"s. To be correct, this is the way that they should be used:

• kbps or kb/s = kilo bits per second
• kBps or kB/s = kilo Bytes per second
• Mbps or Mb/s = Mega bits per second
• MBps or MB/s = Mega Bytes per second

So, only the b or B really matter and mean something different. Since, a "B" is eight times as big as a "b", then 100 kBps is eight times as big as 100 kbps.

Why is the M different? Trust me when I say you should just accept it. Or, I could get into an engineering discourse until you fall asleep:) The important thing is that only the "b/B" pair make a difference in the number.

Now let's try to decipher the real number behind the code. If I told you that my upload speed is 1.5 Mbps, what does that mean? Let's break it down:

1.5 is just 1.5. The capital M means Mega or 1 million (so does a small "m"). The small "b" means bits and the "ps" always means per second. So let's multiply:

1.5 x 1,000,000 x 1 (bit) per second. That comes out to 1,500,000 bits per second.

Let's translate that to Bytes per second. If we divide by 8 since there are 8 bits in a Byte, we get 187,500 Bytes/s. But, we try to make the number in front of the letters as close to a single digit as possible because it looks better so we use Megabits with 1.5 in front.

Now let's look at the upper case "B". My download speed is 8 Mbps. If I write that in Bytes, I just divide by eight since there are eight bits in a Byte.

8 Mbps = 1 MBps

You could see any variation depending on the source. You might see any of these:

8 mbps = 1 MBps = 8000 kbps = 1000 kBps = 8,000,000 bps.

What's the last one? We just drop the first letter and write out the whole number as bits per second. But that's a big number with six zeros so we write 8 Mbps or 8 Mb/s instead.

One more thing. I've simplified the math so that numbers look like even divisions. The truth is that it works a bit differently in practice. For instance, 1 mbps = 1024 kbps = 1048576 bps are the real numbers but that's just computer math. What I've shown you is close enough for estimates and it's easier to do. However...

...if you're still pulling hair out of your head, beard, underarms, or wherever you still grow hair, I'll make it easier for you. Just use the calculator below to play with some upload speed or download speed numbers.

Type a number in the left column field and choose a unit from the list below. Then choose a unit in the right hand list to convert to. The right hand value fills in automatically.