A megabyte is 106 or 1,000,000 bytes.
One megabyte (abbreviated "MB") is equal to 1,000 kilobytes and precedes the gigabyte unit of measurement. While a megabyte is technically 1,000,000 bytes, megabytes are often used synonymously with mebibytes, which contain 1,048,576 bytes (220 or 1,024 x 1,024 bytes).
Data size is also often measured in GB and KB:
1 MB = 1024 KB
1 GB = 1024 MB
MB is not to be confused with Mb, which stands for megabits.