Data Storage Converter
Convert between data storage units, including both the decimal units (KB, MB, GB, TB, based on powers of 1000) and the binary units (KiB, MiB, GiB, TiB, based on powers of 1024). Mixing the two systems is the source of endless confusion, including the classic question of why a 1 TB drive shows less than a terabyte in Windows.
- 1,000 GB in GiB
- 931.322575 GiB
Storage manufacturers use decimal units, so 1 TB means one trillion bytes. Windows measures in binary units but labels them with decimal names, reporting that same drive as roughly 931 GB. Nothing is missing; the two sides are counting with different-sized units.
How it's calculated
1 GB = 10⁹ bytes = 1,000 MB · 1 GiB = 2³⁰ bytes = 1,024 MiB
Decimal units step by 1,000; binary units step by 1,024. The gap compounds at each level: a kilobyte pair differs by 2.4%, but a terabyte versus a tebibyte differs by almost 10% (1 TB = 0.9095 TiB).
Worked example
A 1 TB drive holds 1,000,000,000,000 bytes, which is 931.3 GiB, matching what Windows reports. A 4.7 GB DVD holds 4.38 GiB. A 25 MB email attachment limit fits about 23.8 MiB of data.
Frequently asked questions
›Why does my 1 TB drive show only 931 GB?
The drive really holds 1 trillion bytes. Windows divides by 1024 three times (binary units) but displays the result with the decimal label GB. Formatting overhead takes a little more space on top, but the unit mismatch explains nearly all of the gap.
›What is the difference between MB and MiB?
A megabyte (MB) is 1,000,000 bytes; a mebibyte (MiB) is 1,048,576 bytes (1024²), about 4.9% more. The binary names (kibi, mebi, gibi) were standardized in 1998 precisely to end the ambiguity, though everyday usage still mixes them.
›Are internet speeds measured in the same units?
Connection speeds use bits, not bytes, with a lowercase b: 100 Mbps is 100 megabits per second, which is 12.5 megabytes per second. Divide advertised speed by 8 to estimate download rates in bytes.
›How many photos or songs fit in a gigabyte?
Rough figures: 250 smartphone photos at 4 MB each, or about 200 songs at 5 MB. A two-hour HD movie stream uses about 3 GB, and 4K roughly triples that.
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