File sizes reported by your operating system sometimes don’t match what a decimal conversion predicts, this converter shows both the decimal and binary answer side by side so there’s no confusion about which one you’re seeing.
How to use this kB to MB converter
- Enter a value in the Kilobyte (KB) field to see the equivalent in megabytes.
- Or enter a value in the Megabyte (MB) field to see the equivalent in kilobytes.
- Read both the decimal and binary conversion results.
What this converter does
By convention, 1 MB equals 1000 KB (decimal/SI, base-10), this is the primary result and the one most commonly used for file sizes and storage marketing. However, many operating systems, including Windows, actually compute using binary units where 1 MiB equals 1024 KiB, but label the result “MB” anyway, which is why your OS may show a slightly different, smaller number than a pure decimal conversion would predict.
Decimal: 1 MB = 1,000 KB
Binary: 1 MiB = 1,024 KiB (often mislabeled “MB” by operating systems)
Why your OS shows a different number
Windows and some other operating systems calculate file sizes using powers of 1024 internally but display the result labeled as “MB,” “GB,” etc., rather than the technically correct “MiB,” “GiB.” This mislabeling is the direct cause of confusion when a file’s reported size doesn’t match a straightforward decimal calculation, showing both results side by side removes that ambiguity.
Frequently asked questions
Why does my computer show a different file size than a decimal calculation predicts?
Many operating systems, including Windows, calculate file sizes using binary (1024-based) units internally but label the result with decimal unit names like “MB,” this converter shows both the decimal and binary result so you can see which one your OS is likely using.
How many kilobytes are in a megabyte?
1,000 KB in the decimal (SI) convention, or 1,024 KiB in the binary convention, which operating systems often mislabel as “MB.”
