8 Bits equal 1 Byte. From there there is a debate between hardware and software. HW OEMs call 1000 bytes 1 Kilobyte 1000 KiloBytes a Megabyte, 1000 mega bytes a gigabyte, 1000 gigabytes a Terabyte. From the Software end 1024 Bytes is 1 Kilobyte, 1024 Kilobytes makes a Megabyte, 1024 Megabytes makes a Gigabyte, and 1024 Gigabytes a Terabyte. With each step higher the number becomes more and more separated.
For example here Total undisputed bytes equals 16000000000. That's a straight 16GB to hardware manufacturers, but it is only 14.9012 gigabytes to software people.
Oh! Oh! Oh!!! Another chance for some sleazy lawyers to get rich with a class action like they did with hard drive manufacturers!!! Yeah! I can hardly wait!