Data Storage Converter
Convert file and storage sizes, including both the decimal units drive manufacturers use and the binary units your operating system reports.
All units
How to use the Data Storage Converter
- Enter the size you want to convert.
- Choose the source and target units — note that KB and KiB are different.
- Compare every unit at once in the table below.
Why a 1 TB drive shows as 931 GB
This is the single most confusing thing in digital storage, and it is not a scam — it is two definitions of the same prefix.
Drive manufacturers use decimal units, where 1 TB = 1,000,000,000,000 bytes. Windows reports storage in binary units but labels them with decimal names, so it divides by 1,024 three times and calls the result "GB". The drive really does contain a trillion bytes; that is 931 gibibytes, which Windows displays as 931 GB.
The discrepancy compounds with size: about 2% at kilobyte scale, 5% at gigabyte, and roughly 10% at terabyte. macOS and Linux switched to true decimal reporting years ago, which is why the same drive can show a different figure on different machines.
Decimal and binary units side by side
| Decimal | Bytes | Binary | Bytes |
|---|---|---|---|
| 1 KB | 1,000 | 1 KiB | 1,024 |
| 1 MB | 1,000,000 | 1 MiB | 1,048,576 |
| 1 GB | 10⁹ | 1 GiB | 1,073,741,824 |
| 1 TB | 10¹² | 1 TiB | 1,099,511,627,776 |
The binary prefixes — kibi, mebi, gibi — were standardised by the IEC in 1998 precisely to end this ambiguity. Adoption has been patchy outside Linux and technical documentation.
Bits versus bytes
A byte is eight bits, and the distinction matters most in networking. Internet speeds are quoted in megabits per second (Mb/s), while download managers show megabytes per second (MB/s). Divide by eight to convert: a 100 Mb/s connection downloads at roughly 12.5 MB/s at best.
The capital letter is the only thing distinguishing them — b is bits, B is bytes — which is why marketing material for broadband so often looks better than the speeds you observe.
Frequently asked questions
Should I use MB or MiB?
Use MB for storage marketing and network speeds, MiB when you need the exact binary value — memory sizes, block sizes and technical documentation. If precision matters, state which you mean.
How long will a download take?
Divide the file size in megabits by your connection speed in megabits per second. A 1 GB file is 8,000 megabits, so on a 100 Mb/s line that is at least 80 seconds in ideal conditions.
Why does my phone show less storage than advertised?
Two reasons combine: the decimal-versus-binary gap, and the operating system itself occupying several gigabytes before you install anything.
Is a kilobit 1,000 or 1,024 bits?
In networking, always 1,000. Bit-based units have consistently used decimal prefixes, which is one thing this area gets right.
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