Overview
Convert a storage size between bits, bytes, kilobytes, megabytes, gigabytes, and terabytes, with an explicit toggle between the two competing definitions of "kilobyte" that cause most storage-size confusion in the first place: the decimal definition (1 KB = 1000 bytes, used by drive manufacturers and most marketing) and the binary definition (1 KiB = 1024 bytes, used by operating systems reporting free disk space and by RAM, which is physically addressed in powers of two). A third "show both" mode displays both conversion tables side by side for the same input, which is the fastest way to see exactly why a drive labeled "1 TB" shows up as roughly 931 GiB in a file manager - it's not missing space, it's two different units sharing a similar-looking name. Useful for reconciling advertised storage capacity against what an OS reports, sizing a file transfer or backup, or converting a bandwidth spec into a download time estimate. Runs entirely client-side.
Best for: Reconciling an advertised drive capacity against what your OS actually reports
How to use this tool
- Enter an amount and unit. Any non-negative number, paired with a starting unit from bits up to terabytes.
- Choose decimal, binary, or both. Decimal uses 1000-based units, binary uses 1024-based, and "show both" displays them side by side.
- Read every unit at once. The full conversion table updates live, from bits through the largest unit shown.
Why use this tool
Clears up the KB vs KiB confusion
Explicitly separates the 1000-based and 1024-based definitions instead of picking one silently.
Show-both mode
See exactly how far decimal and binary values diverge for the same input, side by side.
Full range in one view
Bits through terabytes convert together - no need to chain multiple single-pair conversions.
Matches real-world labeling
Decimal mode matches drive manufacturer marketing; binary mode matches what most operating systems report.
Frequently asked questions
Drive manufacturers advertise capacity using the decimal definition (1 TB = 1000 gigabytes), while most operating systems report free space using the binary definition (1 TiB = 1024 gibibytes) but often still label it "GB" or "TB" instead of the technically correct "GiB" or "TiB". The drive isn't missing space - a 1,000,000,000,000-byte drive is genuinely 1 decimal TB, it's just roughly 909.5 binary GiB when measured the other way, which is the number your OS is actually showing you.
RAM capacity is almost always a genuine power of two (a "16 GB" stick is physically 16 GiB, since memory addressing is inherently binary), so binary mode matches it exactly. Hard drive and SSD capacities are typically decimal from the manufacturer, which is why the same nominal size looks different depending on which system reports it - use decimal mode to match the box, and binary mode to match what your OS shows after formatting.
No - a byte is defined as 8 bits in both decimal and binary modes, so bit and byte values convert identically regardless of which definition is selected; the decimal/binary distinction only affects the units above byte, starting at kilobyte/kibibyte. Bits matter most for network bandwidth specs (usually quoted in megabits per second), while bytes matter most for file sizes.