1000000 bytes equals 1 megabyte yet 1024 megabytes equals 1 gigabyte?

There are two definitions. The official definition says: * 1,000 × 1,000 bytes (B) = 1,000,000 B = 1 megabyte (MB) * 1,000 (MB) = 1 gigabyte (GB). This is the definition used for hard drives, DVDs, networking, and everything else. There is also another definition based on 1024 instead of 1000, so 1,024 "megabytes" are equal to 1 "gigabyte". These are used for memory. These are more correctly referred to with MiB and GiB instead of MB and GB: * 1,024 × 1,024 B = 1,048,576 B = 1 MiB * 1,024 MiB = 1 GiB