Byte Converter
Convert between bytes, KB, MB, GB, TB and PB, switching between binary (1024) and decimal (1000) units — the source of the "why is my drive smaller" gap.
How it works
bytes = value × base^(from index) · result = bytes ÷ base^(to index) · base = 1024 (binary, KiB/MiB…) or 1000 (decimal, KB/MB…) · order B, KB, MB, GB, TB, PB
Digital storage is counted in bytes, and the larger units step up by a fixed factor — but which factor depends on the convention. The binary standard multiplies by 1024 (2¹⁰) at each step, matching how memory is addressed; the decimal standard multiplies by 1000, matching SI prefixes and how drive makers label their products. That is why a "1 TB" disk shows up as about 931 GB in an operating system that counts in binary: same bytes, different divisor. This converter lets you switch standards explicitly, so you can reconcile a spec sheet with what your computer reports.
Worked example
Take 1 GB in the binary standard. One gigabyte is 1024 megabytes, so the result is 1,024 MB — and 1024³ = 1,073,741,824 bytes. Switch to the decimal standard and 1 GB becomes exactly 1,000 MB and 1,000,000,000 bytes. The 7% gap between the two is the classic "missing" storage.
Sources: Binary prefix — Wikipedia
Frequently asked questions
What is the difference between binary and decimal units?
Binary units step by 1024 (1 KB = 1024 bytes), matching how computer memory works, while decimal units step by 1000 (1 KB = 1000 bytes), matching SI prefixes. Strictly, the binary units should be written KiB, MiB, GiB, but in everyday use "KB/MB/GB" are used for both, which is the source of much confusion.
Why does my 1 TB drive show as ~931 GB?
Manufacturers sell drives in decimal terabytes (1 TB = 1,000,000,000,000 bytes), but many operating systems display capacity in binary units, dividing by 1024 three times. 1,000,000,000,000 ÷ 1024³ ≈ 931 GiB — no storage is missing, it is just counted two different ways.
Should I use binary or decimal?
Use decimal (1000) when matching storage or bandwidth marketing figures, and binary (1024) when matching what Windows or a file manager reports for RAM and disk usage. This tool defaults to binary but switches instantly, so you can compare the two.
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This calculator is for educational purposes. Double-check important results before acting on them.