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Converters

Data Size Converter

Convert between bits, bytes, KB, MB, GB, TB, and PB — decimal or binary, all units at once.

Data Size Converter
Client-side

About this tool

The Data Size Converter takes a value in any unit — bits, bytes, KB, MB, GB, TB, or PB — and instantly shows the equivalent in every other unit, side by side in a results table.

The tool exposes the distinction that trips up most byte-size calculators: decimal vs. binary multiples. Storage vendors typically use decimal (SI) units, where 1 KB = 1000 bytes — this is what your hard drive's rated capacity uses. Operating systems traditionally use binary (powers of 1024), which is why a "500 GB" drive shows up as roughly 465 GB in Windows. This tool's Decimal/Binary toggle switches the entire table between the two systems, and relabels the binary-mode units correctly as KiB, MiB, GiB, TiB, and PiB per the IEC standard, rather than mislabeling 1024-based values as "KB"/"MB".

Common uses: figuring out how many MB a file transfer will actually consume against a data cap, reconciling a "GB" marketing number against what your OS reports, or sizing API payload limits. All arithmetic happens in plain JavaScript in your browser.

FAQ

Why does my 1 TB drive show up as 931 GB in Windows?
Drive manufacturers advertise capacity in decimal units (1 TB = 1000 GB), the SI standard. Windows reports capacity in binary units (1 "GB" displayed is really a GiB = 1024^3 bytes). Converting into binary GiB gives approximately 931 — no data is actually missing.
What is the difference between KB and KiB?
KB traditionally meant 1000 bytes, though it was also informally used for 1024 bytes for years, causing ambiguity. KiB is the unambiguous IEC term that always means exactly 1024 bytes.
Why is a byte 8 bits?
A byte was standardized at 8 bits because 8 bits can represent 256 distinct values, which comfortably covers ASCII and became the universal addressable unit in memory architecture.
Which mode should I use for network bandwidth?
Network speeds are specified in decimal bits per second. Use decimal mode and the "bit" row when converting ISP-advertised speeds; use binary mode when reasoning about how an OS reports file sizes.
Does this tool round the results?
Results are displayed with enough decimal precision to be useful, with trailing zeros trimmed. The underlying calculation itself is not rounded.