Data Size Converter
A data size converter translates a storage or transfer size between units, making explicit the common mix-up between decimal units (KB/MB/GB, 1000-based, used by storage vendors) and binary units (KiB/MiB/GiB, 1024-based, used by operating systems). The KB/GB versus KiB/GiB distinction exists because storage vendors market drives using decimal, 1000-based, units while operating systems have historically reported free space using binary, 1024-based, units — the same physical bytes, counted two different ways, which is the real reason a 1TB drive shows less than 1TB of usable space in Windows or macOS.
How it works
- Enter a value and choose the unit you're converting from and to.
- Read the converted value.
Formula Convert through a common base of bits; decimal units ×1000 per step, binary units ×1024 per step
Frequently asked questions
Why is 1 GB not always exactly 1024 MB?
GB (decimal, 1000-based) and GiB (binary, 1024-based) are different units that get conflated in everyday use. This tool keeps them distinct: GB→MB uses 1000, GiB→MiB uses 1024.
Why does my hard drive show less space than advertised?
Drive manufacturers advertise decimal GB/TB, but operating systems often display binary GiB/TiB — the same physical bytes, different unit, smaller-looking number.
What is a bit vs a byte?
1 byte = 8 bits. Network speeds are usually quoted in bits per second (Mbps); file sizes are usually quoted in bytes (MB) — see the download time calculator for that specific conversion.
Is my data uploaded anywhere?
No. Conversion runs entirely in your browser.
Can I convert a fractional value, like 2.5 GB?
Yes — decimal values are supported throughout, so partial units like 2.5 GB or 0.75 GiB convert normally.