Fenris is right. The principle behind binary Megabytes/Kilobytes etc is quite simple.
1 Kilobyte = 1,024 bytes
1 Megabyte = 1,024 Kilobytes
1 Gigabyte = 1,024 Megabytes
1 Terabyte = 1,024 Gigabytes
and so on. In terms of bytes, this works out at:
1 Kilobyte = 1,024 bytes
1 Megabyte = 1,024 x 1,024 = 1,048,576 bytes
1 Gigabyte = 1,024 x 1,024 x 1,024 = 1,073,741,824 bytes
1 Terabyte = 1,024 Gigabytes = 1,099,511,627,776 bytes
I hope that's useful.