Data Storage Converter
This free converter switches between bits, bytes, kilobytes, megabytes, gigabytes, terabytes and petabytes, showing both the decimal value manufacturers use and the binary value (KiB, MiB, GiB) Windows counts in, side by side. Type any amount in any unit and see instantly why a 500 GB drive reads as about 465 GB in Windows.
500 GB ≈ 465.7 GiB
Same amount of data, decimal (GB) and binary (GiB) side by side.
What is a data storage converter?
It turns an amount of digital storage, bits, bytes, kilobytes, all the way to petabytes, into any other unit, and shows both systems computing actually uses at once: decimal (base 1,000, the SI standard drive manufacturers advertise) and binary (base 1,024, the count Windows reports). macOS and iOS have counted in decimal since 2009, which is why the same drive can show two different sizes on two computers.
| System | Unit example | 1 unit equals |
|---|---|---|
| Decimal (SI) | Gigabyte (GB) | 1,000,000,000 bytes |
| Binary (IEC) | Gibibyte (GiB) | 1,073,741,824 bytes |
Those two numbers differ by about 7.4%, and it compounds at every step up the ladder. That gap is the entire reason a "500 GB" drive reads as roughly 465 GB once it is plugged in.
How do you use it?
Type an amount. Enter any number, in any unit.
Pick the unit. Units are grouped decimal first, binary second, so you always know which system you are starting from.
Read the headline. The main result pairs your number with the matching unit in the other system, GB with GiB, MB with MiB, and so on.
Scan the full ladder. Every unit from byte to tebibyte updates below at once, with your unit and its pair highlighted.
What doesn't this converter do?
It doesn't convert internet or network speed. Bandwidth is measured in bits per second (Mbps, Gbps), a rate over time, while this tool converts storage size, a fixed amount of data. The two get confused constantly, since a "100 Mbps" connection moves only 12.5 megabytes per second of actual file, an eightfold gap that catches people off guard mid-download. Converting a connection speed into an estimated download time is a different calculation with a different unit (time), so it is not part of this converter.
Why does storage math work this way?
Computers count in powers of two, not ten, because binary is what the hardware actually does. Early computing borrowed "kilo," "mega," and "giga" from the metric system as a convenient shorthand for the nearest power of two, 1,024 instead of 1,000, and the approximation was close enough that nobody minded for decades. Storage got big enough that the 2.4% gap at the kilobyte level became a 7.4% gap at the gigabyte level and a real number of missing-looking bytes, so the IEC introduced kibibyte, mebibyte, and gibibyte in 1998 to name the binary values properly. Drive makers kept the decimal meaning, because it is also the honest one: a "1 TB" drive really does ship with 1,000,000,000,000 bytes.
Real ways people use this
Checking whether a new drive, phone, or cloud plan actually holds what it claims before assuming something is missing. Converting a file or backup size between units when planning storage or a transfer. Working out RAM, VRAM, or cache sizes in the unit a spec sheet uses. Sanity-checking a bill from a cloud storage provider that lists usage in a different unit than the plan.
Frequently asked questions
Why does my hard drive show less space than advertised?
Drive makers count in decimal gigabytes (1 GB = 1,000,000,000 bytes), the standard set by the SI system, while Windows reports binary gibibytes but labels them "GB" (1 GiB = 1,073,741,824 bytes). A 500 GB drive is exactly 500,000,000,000 bytes, which Windows shows as about 465.7. macOS and iOS count in decimal, so they show the full 500 GB.
Is a gigabyte 1000 or 1024 megabytes?
A gigabyte (GB) is 1,000 megabytes, following the decimal system used in the SI standard and by every drive manufacturer. The binary equivalent, a gibibyte (GiB), is 1,024 mebibytes (MiB). Windows displays GiB values while labeling them GB, which is the real source of the confusion between the two numbers.
What is the difference between GB and GiB?
GB (gigabyte) is decimal, exactly 1,000,000,000 bytes, the unit drive manufacturers advertise. GiB (gibibyte) is binary, exactly 1,073,741,824 bytes, about 7.4% larger. The IEC introduced GiB in 1998 so binary and decimal values would have distinct names, though Windows still calls GiB values "GB" on screen.
How many bytes are in a bit?
A bit is one eighth of a byte, so 8 bits make 1 byte. Bits (lowercase b) measure single binary digits and usually show up in network speeds, like megabits per second. Bytes (uppercase B) measure 8 bits together and are the standard unit for file and storage sizes, which is why the two are easy to mix up.
What is a kibibyte (KiB)?
A kibibyte is the binary equivalent of a kilobyte: exactly 1,024 bytes instead of 1,000. The IEC introduced it in 1998, in IEC 60027-2, now part of IEC 80000-13, so "kilo" could keep its normal decimal meaning everywhere else while computing kept its traditional power-of-two counting under a distinct name, KiB, MiB, GiB and so on.
Does this convert internet speed, like Mbps?
No, on purpose. Internet speed is measured in bits per second (Mbps, Gbps), a rate over time, while this tool converts storage size, an amount of data at rest. Mixing the two is another common source of confusion, since 8 megabits equal only 1 megabyte, so a 100 Mbps connection moves at most 12.5 megabytes of file per second.
How many MB are in a GB?
1,000 megabytes make 1 gigabyte in the decimal system that drive manufacturers and most file size listings use. In the binary system Windows uses instead, 1,024 mebibytes (MiB) make 1 gibibyte (GiB). This converter shows both at once, so you can see which figure a given number refers to.
Why does a 1TB drive show as 931GB?
A 1 TB drive holds exactly 1,000,000,000,000 bytes, the decimal terabyte manufacturers advertise. Windows divides that by 1,073,741,824 (1 GiB) instead of 1,000,000,000, giving about 931.3, and labels it "GB" even though it is really GiB. A Mac shows the full 1 TB. No storage is missing, it is the same bytes, counted in the larger binary unit.
What's the difference between little-b bit and big-B byte?
Case matters here: a lowercase b is a bit, and an uppercase B is a byte, which equals 8 bits. A connection speed of 100 Mb/s (100 megabits per second) is only 12.5 MB/s (megabytes per second) of actual file transfer, an eightfold difference that catches people off guard when downloads feel slower than the advertised speed.
How accurate is this converter?
Fully accurate for the unit definitions involved: decimal units follow the SI standard (powers of 1,000) and binary units follow IEC 80000-13 (powers of 1,024) exactly, with no rounding until the number is displayed. The only variable is which system a given device or piece of software chose to report in, which this tool shows side by side.
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Built and tested by the ÆON Toolhub team. Last updated: October 13, 2026. How we test our tools