About the Data Storage Converter
Convert file and drive sizes between bits, bytes, megabytes, gigabytes and terabytes, including binary units like GiB that operating systems use.
Key features
- Convert bits, bytes, kB, MB, GB and TB (decimal)
- Binary units: KiB, MiB, GiB and TiB (1024-based)
- Explains why a 1 TB drive shows as 931 GB
- Swap direction with one click
- See the value in every unit at once
- Free, instant, no sign-up
Bytes, bits and binary prefixes
File sizes, disk capacity, memory and internet speeds use similar-looking units that mean different things. This converter handles both the decimal (SI) units used by drive makers and network providers, and the binary (IEC) units used by operating systems and RAM.
Decimal vs binary units
| Decimal (SI) | Bytes | Binary (IEC) | Bytes |
|---|---|---|---|
| 1 kB | 1,000 | 1 KiB | 1,024 |
| 1 MB | 1,000² | 1 MiB | 1,048,576 |
| 1 GB | 1,000³ | 1 GiB | 1,073,741,824 |
| 1 TB | 1,000⁴ | 1 TiB | 1,099,511,627,776 |
The gap grows with each prefix: ~2.4% at kilo, ~7.4% at giga and ~10% at tera.
Advertised vs reported capacity
| Advertised | Shown in Windows |
|---|---|
| 128 GB | 119 "GB" (GiB) |
| 256 GB | 238 "GB" |
| 512 GB | 477 "GB" |
| 1 TB | 931 "GB" |
| 2 TB | 1.82 "TB" |
macOS uses decimal units, so a 1 TB drive shows as 1 TB there.
Bits and internet speed
| Plan | Max download speed |
|---|---|
| 25 Mbps | 3.1 MB/s |
| 100 Mbps | 12.5 MB/s |
| 500 Mbps | 62.5 MB/s |
| 1 Gbps | 125 MB/s |
Related tools
Need to shrink a file? Try the Image Compressor, or convert anything else with the Unit Converter.
How to use the Data Storage Converter
- Enter your numbers in the fields above. Units and options can be changed at any time.
- The result updates instantly as you type; there's no calculate button to press.
- Check the breakdown under the main result for the details behind the number.
- Adjust the inputs to compare scenarios, for example a different rate or term.