Data Storage Converter
Convert between bits, bytes, KB, MB, GB, and TB — with a toggle for decimal (1000-based) vs binary (1024-based) units.
Decimal vs binary — why storage sizes never quite match
Hard drive and SSD manufacturers advertise capacity using decimal units, where 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes, and so on. Operating systems, however, often report file and drive sizes using binary units, where 1 KiB = 1,024 bytes. This mismatch is exactly why a drive labelled '1 TB' shows up as roughly 931 GB in Windows or macOS — no storage is missing, it's just being measured with a different definition of the unit.
Worked example
1 decimal gigabyte (GB) = 1,000 megabytes (MB). But 1 binary gibibyte (GiB) = 1,024 mebibytes (MiB) — the same nominal 'GB to MB' conversion gives a different number depending on which system you're using, which is why this calculator lets you pick.
Frequently asked questions
Which mode should I use?
Use decimal if you're comparing manufacturer-advertised storage capacity (hard drives, SSDs, USB sticks). Use binary if you're checking a size reported by your operating system's file explorer, since most OSes historically use binary-based KiB/MiB/GiB internally even when labelling them KB/MB/GB.
Is a bit the same as a byte?
No — 8 bits make 1 byte. Bits are typically used for network/internet speeds (megabits per second, Mbps), while bytes are used for file and storage sizes (megabytes, MB) — mixing the two up is a common source of confusion when checking download speeds against file sizes.