How many kilobytes are in a megabyte?

1 megabyte (MB) = 1,000 kilobytes (KB) in the SI decimal system used by hard drive manufacturers, network providers, and most operating systems. In binary, 1 mebibyte (MiB) = 1,024 kibibytes (KiB).

What is the difference between KB and KiB?

KB (kilobyte) uses the decimal prefix: 1 KB = 1,000 bytes. KiB (kibibyte) uses the binary prefix: 1 KiB = 1,024 bytes. The gap is 2.4 %. This tool shows both so you can compare them side by side.

Why do operating systems show different file sizes than storage labels?

Storage manufacturers use SI decimal (1 MB = 1,000 KB), while older Windows versions label binary mebibytes as "MB". A 1 MB file to Windows is actually 1,024 KB in binary. This tool follows the SI convention with a separate binary column.

Is 1 MB exactly 1,000 KB?

Yes, in the SI decimal system: 1 MB = 1,000 KB exactly. This is the standard used by network providers, USB drives, SSDs, and most cloud storage services.

How do I convert MB to KB without a calculator?

Multiply the MB value by 1,000 to get decimal KB. For example, 3.5 MB × 1,000 = 3,500 KB. For binary KiB, multiply by 1,024 instead.

Megabytes to Kilobytes Converter

Name: Megabytes to Kilobytes Converter
Availability: InStock
Author: Nham Vu

Enter a megabyte value and instantly see the decimal KB result plus binary KiB equivalent.

MB to KB Converter

Megabytes (MB)

Decimal: 1 MB = 1,000 KB (SI, IEC 80000-13).
Binary: 1 MiB = 1,024 KiB (IEC 60027-2).

Enter megabytes above to see the result

Common File Sizes

Click to load

File type	MB	KB (decimal)

Summary

Enter a megabyte value and instantly see the decimal KB result plus binary KiB equivalent.

How it works

Enter a value in the Megabytes (MB) field — the KB result updates instantly.
The decimal result uses 1 MB = 1,000 KB (SI standard used by storage manufacturers and networks).
Binary equivalents (MiB → KiB) appear below using 1 MiB = 1,024 KiB.
Click any row in the reference table to load a common file size.
Click "Clear" to reset the converter.

Use cases

Check whether a 2.5 MB photo exceeds a 2,000 KB upload limit.
Compare file sizes listed in MB against KB quotas or thresholds.
Understand the difference between SI decimal KB and binary KiB readings.
Estimate data usage when a plan is quoted in KB but files are shown in MB.
Convert software patch sizes from MB to KB for bandwidth planning.

Frequently Asked Questions

Last updated: 2026-07-24 · Reviewed by Nham Vu