File Size Converter
Free file size converter. Convert between bytes, kilobytes (KB), megabytes (MB), gigabytes (GB), terabytes (TB), and their binary equivalents (KiB, MiB, GiB). Understand storage capacities at a glance.
Understanding File Size Units
File sizes are measured in bytes and multiples of bytes. There are two standards: decimal (SI), which uses powers of 1000 (KB, MB, GB, TB, PB), and binary (IEC), which uses powers of 1024 (KiB, MiB, GiB, TiB). Operating systems and storage manufacturers often mix the two, leading to confusion about actual capacity.
Decimal vs. Binary: What Is the Difference?
In the decimal system, 1 KB = 1,000 bytes and 1 MB = 1,000,000 bytes. In the binary system, 1 KiB = 1,024 bytes and 1 MiB = 1,048,576 bytes. The gap grows at larger scales: 1 TB equals 1 trillion bytes (10^12), while 1 TiB equals 1,099,511,627,776 bytes (2^40) -- roughly 10% more.
Frequently Asked Questions
Why does my hard drive show less space than advertised?
Drive manufacturers use the decimal system (1 GB = 1,000,000,000 bytes), while most operating systems report sizes in binary (1 GiB = 1,073,741,824 bytes). A 500 GB drive therefore shows approximately 465 GiB in your OS -- the missing space is not lost, just measured differently.
Which standard should I use?
If you work with networking or storage marketing, decimal units (KB, MB, GB) are standard. If you are a developer or system administrator dealing with RAM or OS-level file sizes, binary units (KiB, MiB, GiB) are more precise.