How to Use the Data Storage Unit Converter
Converting a file size or drive capacity between units by hand often means losing track of how many times to multiply or divide by 1024. This calculator takes a value, a source unit, and a target unit, and instantly converts between B (bytes) all the way up to PB (petabytes).
Data storage units actually have two different bases in common use. The binary basis (1KB = 1024B) is what computers use internally, while the decimal basis (1KB = 1000B) is what storage manufacturers commonly use for marketing. Since the same input value converts to slightly different results depending on which basis you use, this calculator lets you pick either one.
This difference explains why a "1TB" drive often shows up as roughly 931GB in Windows. The manufacturer labels it using the decimal basis (1TB = 1,000,000,000,000 bytes), but Windows reports capacity using the binary basis (1TiB = 1,099,511,627,776 bytes), so the same physical drive appears smaller once you plug it in. Pick the basis that matches what you're comparing against for an accurate conversion.
Frequently Asked Questions
Computers are binary, so 1KB = 1024B is the technically correct basis. Storage manufacturers often use 1KB = 1000B for marketing, which is why an advertised capacity can look smaller than expected once installed.
Windows typically reports capacity on a 1024 basis, while the packaging uses a 1000 basis, so the same physical capacity ends up showing two different numbers.