How many bits in 20 mega bytes?

1 Bit is the smallest recordable state ( Zero or One / ON or Off / High or Low ) 1 Byte is 8 Bits which can represent a number upto 256 ( 28) or a character 1 KiloBytes (KB) is 210 Bytes == 1024 Bytes //// "Slang" as One Thousand 1 MegaBytes (MB) is 2**20 Bytes = 210 * 210 Bytes 1,045,876 Bytes //// "Slang" as One Million 1 GigaByte (GB) is 2**30 == 1,073,741,824 //// "Slang" as One Billion So 20 Gigabytes is 20 * 230 Bytes 1 TeraByte (GB) is 240 == 1,099,511,627,776 //// "Slang" as One Trillion From the above, you can see why a 32 bit operating system can address upto 4 GB of memory (2**32 4GB if your computer has 4GB of RAM and a 32 bit OS, it will not be able to address it all since some of that address is used by video cards and other devices. This is why most PCs have either 3GB (or less) with a 32 bit OS or MORE & MORE ( 4+GB with 64 Bit OS)