How many KB are in 1 MB (SI/decimal)?

In the SI (International System of Units) standard, 1 megabyte (MB) equals exactly 1,000 kilobytes (KB). This is how storage manufacturers and network speed tests typically report sizes.

How many KiB are in 1 MiB (binary/IEC)?

In the IEC binary standard, 1 mebibyte (MiB) equals exactly 1,024 kibibytes (KiB). Windows File Explorer and many operating systems use this standard while displaying "MB".

Why are there two different standards?

The SI standard uses powers of 10 (1,000), matching everyday metric prefixes. The binary standard uses powers of 2 (1,024), which aligns naturally with how computers address memory. The IEC introduced distinct names (KiB, MiB) in 1998 to eliminate ambiguity.

Which standard does Windows use?

Windows historically displays file sizes using binary calculations (multiples of 1,024) but labels them "KB" and "MB" instead of "KiB" and "MiB". So a file shown as 1 MB in Windows Explorer is actually 1 MiB = 1,048,576 bytes.

Which standard does macOS use?

Since macOS 10.6 (Snow Leopard), Apple switched to SI decimal units, so 1 MB in macOS Finder equals exactly 1,000,000 bytes.

Is 1 KB equal to 1,000 or 1,024 bytes?

In the SI standard, 1 KB = 1,000 bytes. In the binary/IEC standard, 1 KiB = 1,024 bytes. The difference is small for kilobytes but grows significantly at higher units like gigabytes and terabytes.

Kilobytes to Megabytes Converter

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

Enter a value in kilobytes to get the megabyte equivalent in both SI (1000) and binary (1024) standards instantly.

File Size Converter

Kilobytes (KB)

Megabytes (MB) — SI decimal

Enter a value on the left to see results

Common File Size Reference

Click a row to load it

File / Context	KB	MB (SI)	MiB (bin)

Summary

Enter a value in kilobytes to get the megabyte equivalent in both SI (1000) and binary (1024) standards instantly.

How it works

Type a value in the Kilobytes field to see the result in Megabytes.
Switch to MB input mode to convert Megabytes back to Kilobytes.
Results are shown for both SI (1 MB = 1,000 KB) and binary (1 MiB = 1,024 KiB) standards simultaneously.
Click any row in the reference table to load that file size into the converter.
Click "Clear" to reset all fields.

Use cases

Understand file sizes when downloading or uploading documents and images.
Compare storage capacities reported by operating systems (binary) vs. drive manufacturers (decimal).
Convert file size limits specified in KB into MB for quota planning.
Quickly reference how many kilobytes fit in common megabyte thresholds.
Verify attachment size limits for email or web forms.
Convert data transfer measurements between KB/s and MB/s.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu