Kilobytes and megabytes
A kilobyte (kB) is 1,000 bytes in the SI decimal system. Small files such as text documents, icons and emails are measured in kilobytes.
A megabyte (MB) is 1,000,000 bytes, or 1,000 kB, in the decimal system. Photos, songs, app downloads and email attachment limits are measured in megabytes.
Worked example
Convert 750 kB: 750 × 0.001 = 0.75, so 750 kilobytes is 0.75 megabytes. Likewise 100 kB = 0.1 MB.
Estimating in your head
The factor is a power of ten, so just move the decimal point 3 places to the left: 750 kB = 0.75 MB.
Going the other way
To convert megabytes to kilobytes, divide by 0.001 (or multiply by 1,000). The swap button between the boxes opens that page.
How this works
MB = kB × 0.001
1 kB = 1,000 B and 1 MB = 1,000,000 B, both by definition, so the factor is their ratio: 0.001 exactly. Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.
Frequently asked
How many megabytes are in a kilobyte?
1 kilobyte = 0.001 megabytes, exactly. The value follows from the unit definitions, so it never changes.
How do I convert kilobytes to megabytes?
Multiply by 0.001. For example, 100 kB × 0.001 = 0.1 MB.
What is 1,000 kB in megabytes?
1,000 kB = 1 MB. The table next to the converter lists more common values.
Is the result rounded?
Only on screen. The page computes with the exact definitions and removes floating-point noise past 15 significant digits; pick 3 to 12 significant figures, or use Copy result for the full value.
Sources
- NIST — Prefixes for binary multiples (IEC 80000-13)
- BIPM — The International System of Units (SI Brochure), 9th edition
- Wikipedia — Byte
Reviewed Oct 17, 2026 · test vectors fixtures/units/data/kb-to-mb/