File Size Converter — Bytes, KB, MB, GB, TB
Convert between file size units instantly. See both binary (1024-based: KiB, MiB, GiB) and decimal (1000-based: KB, MB, GB) conversions side by side.
Frequently Asked Questions
What is a kilobyte?
A kilobyte (KB) is a unit of digital information equal to 1,000 bytes in the decimal (SI) system or 1,024 bytes in the binary (IEC) system (technically a kibibyte, or KiB). Most operating systems and storage manufacturers use different conventions, which is why file sizes can appear inconsistent.
What is the difference between KB and KiB?
KB (kilobyte) uses the SI standard where 1 KB = 1,000 bytes. KiB (kibibyte) uses the IEC binary standard where 1 KiB = 1,024 bytes. The difference grows at larger scales: 1 TB = 1,000,000,000,000 bytes while 1 TiB = 1,099,511,627,776 bytes — a gap of nearly 10%.
How many MB in a GB?
In decimal (SI) units: 1 GB = 1,000 MB. In binary (IEC) units: 1 GiB = 1,024 MiB. When your OS reports a "1 GB" file, it usually means 1 GiB (1,073,741,824 bytes), while storage manufacturers label drives using the SI definition (1,000,000,000 bytes).
Why do hard drives show less space than advertised?
Hard drive manufacturers measure capacity in decimal units (1 GB = 1,000,000,000 bytes), but operating systems like Windows display sizes in binary units (1 GiB = 1,073,741,824 bytes). A "500 GB" drive contains 500,000,000,000 bytes, which the OS reports as approximately 465 GiB. Additionally, some space is used by the file system and partitioning overhead.
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