How this conversion works
A byte is 8 bits. Storage prefixes come in two families: decimal (SI) prefixes where 1 kB = 1,000 bytes, 1 MB = 1,000,000 bytes and so on, and binary (IEC) prefixes where 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes and so on.
Drive makers label capacity in decimal units, while some operating systems report sizes in binary units but label them “GB”. That is why a new 1 TB drive may show as about 931 “GB”.
Formula: result = value × (base units per source unit) ÷ (base units per target unit)
Where this conversion is used
- Understanding why a 1 TB drive shows about 931 GB in an operating system that counts in binary units.
- Comparing internet speeds in megabits per second with file sizes in megabytes.
- Cloud storage plans and file upload limits.
- Memory and storage specifications that mix decimal and binary prefixes.
Worked example: 1 TB drive in GiB
- 1 TB = 1,000,000,000,000 bytes.
- 1 GiB = 1,073,741,824 bytes.
- 1,000,000,000,000 ÷ 1,073,741,824 ≈ 931.32 GiB.
Unit definitions
| Unit | In bytes | Note |
|---|---|---|
| Bit (b) | 0.125 | |
| Byte (B) | 1 | |
| Kilobyte (kB) | 1,000 | |
| Megabyte (MB) | 1,000,000 | |
| Gigabyte (GB) | 1,000,000,000 | |
| Terabyte (TB) | 1,000,000,000,000 | |
| Petabyte (PB) | 1e15 | |
| Kibibyte (KiB) | 1,024 | |
| Mebibyte (MiB) | 1,048,576 | |
| Gibibyte (GiB) | 1,073,741,824 | |
| Tebibyte (TiB) | 1,099,511,627,780 | |
| Kilobit (kbit) | 125 | |
| Megabit (Mbit) | 125,000 | |
| Gigabit (Gbit) | 125,000,000 |
Gigabytes to gibibytes
| Gigabyte (GB) | Gibibyte (GiB) |
|---|---|
| 1 | 0.9313 |
| 16 | 14.9012 |
| 32 | 29.8023 |
| 64 | 59.6046 |
| 128 | 119.2093 |
| 256 | 238.4186 |
| 500 | 465.6613 |
| 1,000 | 931.3226 |
| 2,000 | 1,862.6451 |
Megabits to megabytes
| Megabit (Mbit) | Megabyte (MB) |
|---|---|
| 1 | 0.125 |
| 10 | 1.25 |
| 50 | 6.25 |
| 100 | 12.5 |
| 300 | 37.5 |
| 500 | 62.5 |
| 1,000 | 125 |
Things to watch for
- Internet speeds are quoted in bits per second (Mbps). Divide by 8 for megabytes per second.
Precision and sources
Results are calculated from the definitions above and rounded to 12 significant digits; the converter shows up to eight decimal places and the tables four. Reference: IEC 80000-13:2008, Quantities and units — Information science and technology.
Frequently asked questions
Is a kilobyte 1,000 or 1,024 bytes?
Under the SI and IEC standards a kilobyte (kB) is 1,000 bytes and a kibibyte (KiB) is 1,024 bytes. Older software sometimes used “KB” for 1,024.
How many megabytes per second is 100 Mbps?
12.5 MB/s (100 ÷ 8), before network overhead.