Data Storage Converter
Convert file and storage sizes. Choose decimal (what most operating systems label KB/MB/GB) or binary (the actual power-of-1024 values) units.
Decimal vs. binary — why your drive looks smaller than advertised
Storage manufacturers use decimal units, where 1 GB = 1,000,000,000 bytes. Most operating systems historically reported binary units while still calling them "GB" — where 1 GiB = 1,073,741,824 bytes is about 7% larger than 1 GB. That mismatch is why a "1 TB" drive shows up as roughly 931 GB in your file manager.
Frequently asked
Why does my 1TB drive show less than 1000 GB in Windows?
The drive is sized in decimal terabytes (1,000,000,000,000 bytes) by the manufacturer, but many systems display the binary equivalent using the same "GB" label — which comes out to roughly 931 GiB for a decimal 1TB drive.
What's the difference between MB and MiB?
MB (megabyte) is 1,000,000 bytes in the decimal system this tool's "Decimal" category uses. MiB (mebibyte) is 1,048,576 bytes — exactly 1024², used in the "Binary" category — and is the technically unambiguous unit for power-of-two sizes.