Two parallel systems
Decimal vs binary data units
| Decimal (SI) | Bytes | Binary (IEC) | Bytes |
|---|---|---|---|
| 1 kB | 1,000 | 1 KiB | 1,024 |
| 1 MB | 1,000,000 | 1 MiB | 1,048,576 |
| 1 GB | 1,000,000,000 | 1 GiB | 1,073,741,824 |
| 1 TB | 1,000,000,000,000 | 1 TiB | 1,099,511,627,776 |
Why drives 'lose' space
Storage manufacturers advertise capacity in decimal units (1 TB = 10¹² bytes). macOS Finder also reports decimal. Windows Explorer and Linux ls -h, however, use binary units and label them MB/GB — confusingly using the decimal abbreviation. A 1 TB drive really does hold one trillion bytes — that's 931 GiB.
Convert data sizes
MB ↔ MiB
Megabyte (MB)
Mebibyte (MiB)
Press / to focus
| Unit | 1 MB equals |
|---|---|
| Bit (b) | 8.00000e+6 |
| Byte (B) | 1.00000e+6 |
| Kilobyte (KB) | 1,000 |
| Megabyte (MB) | 1 |
| Gigabyte (GB) | 0.001 |
| Terabyte (TB) | 0.000001 |
| Petabyte (PB) | 1e-9 |
| Kibibyte (KiB) | 976.563 |
| Mebibyte (MiB) | 0.953674 |
| Gibibyte (GiB) | 0.000931323 |
| Tebibyte (TiB) | 9.09495e-7 |
Networking is always decimal
Internet speeds (Mbps, Gbps) use SI decimal units. To estimate download time in seconds, divide file size in megabits by your line speed in Mbps.
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