A Megabyte, or MB, is generally defined in decimal when referring to storage capacity—so that is 1,000,000 bytes. In binary, a megabyte can be 1,024 kilobytes, which is 1,048,576 bytes. To sum up the common definitions: 1 MB = 1,000 KB = 1,000,000 bytes (decimal). In binary, 1 MB = 1,024 KB = 1,048,576 bytes.