There are two common ways to define the relationship between kilobytes (KB) and megabytes (MB), depending on whether you use the decimal (SI) system or the binary system:

• Decimal (SI) system:
  1 megabyte (MB) = 1,000 kilobytes (KB)
  This is based on powers of 10, where 1 KB = 1,000 bytes and 1 MB = 1,000,000 bytes

• Binary system (commonly used in computing):
  1 megabyte (MB) = 1,024 kilobytes (KB)
  Here, 1 KB = 1,024 bytes and 1 MB = 1,048,576 bytes (2^20 bytes)

Summary:

System| 1 MB equals how many KB?
---|---
Decimal (SI)| 1,000 KB
Binary| 1,024 KB

The binary system is more common in operating systems and computer memory contexts, while the decimal system is often used for storage device capacities and data transfer rates. Therefore, depending on context, there are either 1,000 KB or 1,024 KB in 1 MB