KB to MB Converter

KB & MB Converter

Convert between kilobytes and megabytes using binary (1024) conversion. Essential for file sizes, storage capacity, and data transfer calculations.

Last updated: March 2026 | By Patchworkr Team

Binary vs Decimal

There are two systems for measuring data: binary (base-2) and decimal (base-10). This calculator uses the binary system. Operating systems vary in usage: Windows and RAM applications use binary (base-1024), while modern systems like macOS and storage manufacturers use decimal (base-1000).

Decimal (SI standard): 1 KB = 1,000 bytes, 1 MB = 1,000 KB, 1 GB = 1,000 MB.
Binary (computing standard): 1 KiB = 1,024 bytes, 1 MiB = 1,024 KiB, 1 GiB = 1,024 MiB.
The terms MiB, GiB, etc. were standardized to eliminate ambiguity. However, MB is still informally used in both contexts, which causes confusion in practice.

Real-world example: a "1 GB" USB drive has 1 billion bytes (manufacturer marketing, decimal). Windows shows this as 953 MiB (binary calculation), not 1,000 MB. Both are correct—they just use different standards.

Storage Units

Byte (B)
1 B
Basic unit. 1 byte = 8 bits.
Kibibyte (KiB)
1,024 B
Binary: 1,024 bytes. Common for text files in computing.
Mebibyte (MiB)
1,024 KiB
Binary: 1,024 KiB. Photos, documents, small videos.
Gibibyte (GiB)
1,024 MiB
Binary: 1,024 MiB. Movies, games, large files.
Tebibyte (TiB)
1,024 GiB
Binary: 1,024 GiB. Hard drives, large storage.

Common File Sizes

Text email5-20 KB
MP3 song (4 min)3-5 MB
High-res photo2-8 MB
PDF document100 KB - 5 MB
HD movie (2 hrs)4-8 GB
Video game20-100 GB

Frequently Asked Questions

How many KB in a MB?

In binary (computer) notation: 1 MB = 1,024 KB. In decimal (SI) notation: 1 MB = 1,000 KB. This calculator uses binary, which is standard for file sizes and memory.

Why 1024 instead of 1000?

Computers use binary (base-2). 1024 = 2¹⁰, which is the closest power of 2 to 1000. This makes binary math efficient for computers, which is why storage is measured in powers of 1024.

What is the difference between MB and MiB?

MB (megabyte) = 1,000 KB per SI standard. MiB (mebibyte) = 1,024 KiB (binary). The "i" distinguishes binary units. Confusion arises because "MB" is often used informally for binary contexts, but the formal standard reserves MB for decimal (1,000) and MiB for binary (1,024).

Why does my 1 TB drive show as 931 GB?

Drive manufacturers use decimal (1 TB = 1,000 GB), but operating systems use binary (1 TB = 1,024 GB). 1 trillion bytes = 931 binary GB but 1,000 decimal GB. Both are correct for their systems.

Which system should I use?

Use binary (1024) for RAM, file systems in Windows/Linux, and technical measurements. Use decimal (1000) for storage marketing claims and international SI standards. When unclear, check your OS: Windows reports in binary MiB/GiB, macOS in decimal MB/GB. This calculator uses binary (1024) since it's standard for file and memory operations.

How do I convert MB to GB?

Divide MB by 1,024 to get GB (binary). For example, 5,120 MB ÷ 1,024 = 5 GB. Use our MB to GB converter for automatic calculations.

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