Data Storage Converter

Storage units get confusing fast because two different counting systems are used side by side — decimal units (powers of 1,000) used by drive manufacturers, and binary units (powers of 1,024) typically used by operating systems. This converter handles the math between bits, bytes, KB, MB, GB, TB, and PB, using whichever convention you specify.

What the Result Means

Enter a value in one unit and the calculator converts it to the unit you choose, using either the decimal (1,000-based) or binary (1,024-based) convention depending on which you select. The result is the equivalent amount of data expressed in your target unit — useful for translating a manufacturer’s advertised drive capacity into what your OS will actually display, converting a file size between MB and GB, or working out how many gigabytes a given number of megabits represents.

The distinction between decimal and binary matters because it’s the single biggest source of “missing” storage complaints. A drive advertised as 1TB using decimal units (1,000,000,000,000 bytes) shows up as roughly 931GB in an operating system that reports space using binary units (1,024-based GiB, often just labeled “GB” in the interface). No data actually goes missing — it’s the same number of bytes, described with two different yardsticks.

How This Calculator Works

The two conventions use different multipliers between each step up in unit size:

• Decimal (SI, used for advertised capacity): 1,000 bytes = 1 KB, 1,000 KB = 1 MB, 1,000 MB = 1 GB, 1,000 GB = 1 TB.
• Binary (used by most operating systems, technically KiB/MiB/GiB/TiB): 1,024 bytes = 1 KB, 1,024 KB = 1 MB, 1,024 MB = 1 GB, 1,024 GB = 1 TB.
• Bits and bytes: 8 bits = 1 byte, which matters when converting network speeds (measured in bits) into file sizes (measured in bytes).

Worked example: converting a 500GB drive (decimal, as advertised) into what an OS will report:

• 500GB (decimal) = 500,000,000,000 bytes
• 500,000,000,000 bytes ÷ 1,024³ (1,073,741,824) ≈ 465.7 GiB
• So a “500GB” drive shows up as roughly 466GB in most operating systems — again, the same bytes, just a different unit definition, not lost storage.

Important Limitations

• Not every OS labels binary units correctly. Windows displays binary (1,024-based) values but labels them “GB” instead of the technically correct “GiB,” which is the root of most confusion — macOS and Linux more often use decimal units or the correct GiB label depending on version and context.
• Networking figures are almost always decimal and in bits. Internet speeds (Mbps, Gbps) use decimal multiples of bits, not bytes — don’t apply binary conversion to a connection speed.
• Rounding compounds at larger scales. The percentage difference between decimal and binary units grows at each step up (about 2.4% at KB, but roughly 7% by the TB level), so always convert with the correct base rather than approximating.
• File sizes reported by different tools can vary slightly. Some software reports sizes in decimal, others in binary, which can make the same file appear to have two different sizes depending on where you check.