Megabytes and 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.
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.
Worked example
Convert 2 MB: 2 × 1,000 = 2,000, so 2 megabytes is 2,000 kilobytes. Likewise 5 MB = 5,000 kB.
Estimating in your head
The factor is a power of ten, so just move the decimal point 3 places to the right: 2 MB = 2,000 kB.
Going the other way
To convert kilobytes to megabytes, divide by 1,000 (or multiply by 0.001). The swap button between the boxes opens that page.
How this works
kB = MB × 1,000
1 MB = 1,000,000 B and 1 kB = 1,000 B, both by definition, so the factor is their ratio: 1,000 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 kilobytes are in a megabyte?
1 megabyte = 1,000 kilobytes, exactly. The value follows from the unit definitions, so it never changes.
How do I convert megabytes to kilobytes?
Multiply by 1,000. For example, 5 MB × 1,000 = 5,000 kB.
What is 10 MB in kilobytes?
10 MB = 10,000 kB. 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/mb-to-kb/