About Data Storage Conversion
Data storage uses two parallel systems of prefixes, which is why data storage conversion is more confusing than almost any other unit conversion. The decimal (SI) prefixes — kilobyte, megabyte, gigabyte — are powers of 1000. The binary (IEC) prefixes — kibibyte, mebibyte, gibibyte — are powers of 1024. Both are used every day, often by the same software, sometimes for the same file.
The confusion is not academic. A 1 TB hard drive holds exactly 1,000,000,000,000 bytes as far as the manufacturer is concerned. Windows, macOS and Linux all display that same drive as 931 GiB. Neither number is wrong — they use different units with the same names abbreviated the same way. This tool shows both clearly and always labels which system you are using.
The 16 units supported
| Unit | Symbol | Bytes | System |
|---|---|---|---|
| Bit | b | 0.125 | Base |
| Byte | B | 1 | Base |
| Kilobyte | KB | 1,000 | Decimal (SI) |
| Megabyte | MB | 1,000,000 | Decimal (SI) |
| Gigabyte | GB | 1,000,000,000 | Decimal (SI) |
| Terabyte | TB | 1,000,000,000,000 | Decimal (SI) |
| Petabyte | PB | 10¹⁵ | Decimal (SI) |
| Kibibyte | KiB | 1,024 | Binary (IEC) |
| Mebibyte | MiB | 1,048,576 | Binary (IEC) |
| Gibibyte | GiB | 1,073,741,824 | Binary (IEC) |
| Tebibyte | TiB | 1,099,511,627,776 | Binary (IEC) |
| Pebibyte | PiB | 1,125,899,906,842,624 | Binary (IEC) |
| Kilobit | Kb | 125 | Bits |
| Megabit | Mb | 125,000 | Bits |
| Gigabit | Gb | 125,000,000 | Bits |
| Terabit | Tb | 125,000,000,000 | Bits |
Decimal vs binary — the size gap
| Prefix | Decimal (×1000) | Binary (×1024) | Difference |
|---|---|---|---|
| Kilo / Kibi | 1,000 B | 1,024 B | +2.4% |
| Mega / Mebi | 1,000,000 B | 1,048,576 B | +4.9% |
| Giga / Gibi | 1,000,000,000 B | 1,073,741,824 B | +7.4% |
| Tera / Tebi | 1,000,000,000,000 B | 1,099,511,627,776 B | +10.0% |
| Peta / Pebi | 10¹⁵ B | 1,125,899,906,842,624 B | +12.6% |
Common conversions
| From | To | Factor |
|---|---|---|
| 1 byte | Bits | 8 exactly |
| 1 KB | Bytes | 1,000 exactly |
| 1 KiB | Bytes | 1,024 exactly |
| 1 MB | MiB | 0.953674… approximately |
| 1 GB | GiB | 0.931323… approximately |
| 1 TB | TiB | 0.909495… approximately |
| 1 MiB | MB | 1.048576 exactly |
Why your drive shows less than you paid for
A "1 TB" SSD is advertised as holding 1,000,000,000,000 bytes (decimal). Windows displays the same drive as 931 GiB (binary), because Windows uses binary arithmetic under the hood but historical decimal labels for the numbers. So a 1 TB drive shows as "931 GB" in Windows — even though it physically holds exactly what the manufacturer promised. This is not a scam and not a bug: it is the two systems disagreeing about what the word "giga" means.
USB drive manufacturers often go a step further and format with less usable space than the raw capacity (partition table overhead, preinstalled software), which is why a "64 GB" USB stick might show as 57 GiB in your file manager. That is both the decimal/binary conversion and a bit of vendor padding.
Common use cases
Disk Planning
Compare advertised drive capacity to actual formatted size.
Cloud Storage
Convert between provider decimal quotas and OS binary displays.
Network Speeds
Convert Mbps to MB/s (network speeds are almost always in bits).
Database Sizing
Compare storage quotas to actual row sizes in bytes.
Server Capacity
Plan disk layouts and estimate backup sizes accurately.
Mobile Data
Convert between phone plan quotas (GB) and app data usage (MiB).
Privacy and accuracy
This data storage converter runs entirely in your browser. All conversions use exact definitional factors, so the results are as precise as the input. Nothing is uploaded, stored or logged — safe for confidential data capacity planning.