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Convert digital storage sizes between bytes, kilobytes, megabytes, gigabytes and terabytes — including binary (KiB/MiB/GiB) units.
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Data Size is a free, private online tool that lets you convert digital storage between bytes, KB, MB, GB, TB and binary KiB/MiB/GiB. It runs entirely in your browser, so nothing you enter is uploaded to a server.
Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.
Storage is sold in decimal units (1 KB = 1000 bytes) but operating systems often count in binary (1 KiB = 1024 bytes). That is why a 1 TB drive shows as about 931 GiB.
Decimal: KB, MB, GB, TB (powers of 1000). Binary: KiB, MiB, GiB, TiB (powers of 1024). Bits are 1/8 of a byte.
Estimating file and backup sizes, RAM and disk capacity, and reconciling advertised vs actual drive space.
Digital storage is measured in bytes and their multiples. A byte is eight bits, enough for one character of text. From there the units climb: kilobytes, megabytes, gigabytes and terabytes. This converter moves a value across all of them so you can quickly compare file, memory and disk sizes.
There are two parallel systems. Decimal units use powers of 1000: 1 KB = 1000 bytes, 1 MB = 1,000,000 bytes, used by storage manufacturers and networking. Binary units use powers of 1024 and have distinct names: 1 KiB = 1024 bytes, 1 MiB = 1,048,576 bytes, used by operating systems for memory. The tool supports both so you can reconcile them.
This mismatch explains a classic frustration: a drive sold as '1 TB' (1,000,000,000,000 decimal bytes) is reported by most operating systems as about 931 GiB, because the OS divides by 1024 at each step. No space is missing — the two systems simply count differently. Converting between TB and TiB makes the discrepancy obvious.
Storage is quoted in bytes, but some contexts use bits (one eighth of a byte) — most notably network speeds. Keeping the two straight matters: a file size is in bytes, a connection speed is in bits per second. This tool includes bits so you can convert cleanly between the two when needed.
Estimate whether files fit on a drive or in an email, plan backups and cloud storage, size RAM and databases, and understand the gap between advertised and actual capacity. It runs entirely in your browser.