💾 Data Storage Converter
Convert bytes, kilobytes, gigabytes, and terabytes in either standard binary or decimal formats.
Binary vs Decimal Storage Units
Computer science uses binary bases where 1 KB = 1024 Bytes. Hard drive manufacturers use decimal bases where 1 KB = 1000 Bytes. This is why a "1 TB" drive displays as roughly 931 GB in operating systems. The base selector above switches between the two, and the choice is recorded alongside each result in your history so you can tell later which convention a figure was calculated under.
The gap widens at every step up the scale. At kilobytes the two conventions differ by 2.4%; by gigabytes it is 7.4%, and by terabytes almost 10%. Nothing is being lost and no one is being deceived — the drive really does hold a trillion bytes, but Windows divides by 1024 three times and reports the smaller number. macOS and most Linux distributions switched to decimal years ago, which is why the same drive can report two different capacities on two machines.
A rule of thumb for which to pick: use decimal when the number came off a spec sheet, an invoice, a bandwidth cap or a cloud storage plan, since vendors quote in powers of ten. Use binary when the number came from your own machine — file sizes, RAM, disk usage in a file manager or terminal — because that is what the operating system is almost certainly reporting.