kilobyte (decimal) (kB)
1 kilobyte (decimal) = 1,000 bytes
What is kilobyte (decimal)?
A kilobyte in the decimal (SI) system is a data unit equal to 1,000 bytes. It is used by storage manufacturers and network providers to express file sizes and data transfer rates.
Notes: Decimal prefix
Real-world uses
Kilobytes are used for small text files, email messages, web cookies, and simple HTML documents. A plain text email is typically 2–20 kB. Configuration files, scripts, and small images often fall in the kilobyte range. The unit is less commonly used today as typical files have grown to megabyte scale.
History
The kilobyte emerged in the early computing era when memory and storage were measured in small multiples. The ambiguity between 1,000 and 1,024 bytes arose because early computer engineers found it convenient to use powers of two, and 1,024 was close enough to 1,000 until storage capacities grew large enough to make the 2.4% difference meaningful.
Common mistakes
The decimal kilobyte (1 kB = 1,000 bytes) differs from the binary kibibyte (1 KiB = 1,024 bytes). Operating systems historically used "kB" to mean 1,024 bytes, creating confusion. The IEC introduced "KiB" (kibibyte) in 1998 to distinguish the two, but older usage persists.
When is this conversion used?
Converting kilobyte (decimal) to byte is useful in the data domain when comparing values across different measurement standards or applying formulas that require a specific unit.
How to convert kilobyte (decimal) to byte
To convert kilobyte (decimal) to byte, multiply the value by 1,000.
Conversion formula (from base unit)
x * 1000.0
Measurement standards
The International Electrotechnical Commission (IEC 80000-13) defines binary prefixes: 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes. The SI decimal prefixes (kB = 1,000 bytes, MB = 1,000,000 bytes) apply to data units as they do to all SI quantities.
Did you know?
By 2025, the global datasphere is estimated to reach 181 zettabytes — roughly 181 trillion gigabytes. If stored on standard Blu-ray discs, the stack would reach from Earth to Mars and back over 20 times.
| kilobytes (decimal) | bytes |
|---|---|
| 0.1 | 100 |
| 0.5 | 500 |
| 1 | 1,000 |
| 2 | 2,000 |
| 5 | 5,000 |
| 10 | 10,000 |
| 25 | 25,000 |
| 50 | 50,000 |
| 100 | 100,000 |
| 250 | 250,000 |
| 500 | 500,000 |
| 1,000 | 1,000,000 |
Common values
| kilobytes (decimal) | bytes | |
|---|---|---|
| A text email | 5 kilobytes (decimal) | 5,000 bytes |
| An MP3 song (4 min) | 4,000 kilobytes (decimal) | 4,000,000 bytes |
| A smartphone photo | 5,000 kilobytes (decimal) | 5,000,000 bytes |
| An HD movie | 5,000,000 kilobytes (decimal) | 5.000000e+09 bytes |
| A full hard drive | 1.000000e+09 kilobytes (decimal) | 1.000000e+12 bytes |
Full kilobyte (decimal) conversion table
| Unit | Value | Factor |
|---|---|---|
| byte | 1 kB = 1,000 B | × 1,000 |
| megabyte (decimal) | 1 kB = 0.001 MB | × 0.001 |
| gigabyte (decimal) | 1 kB = 0.000001 GB | × 0.000001 |
| terabyte (decimal) | 1 kB = 1.000000e-09 TB | × 1.000000e-09 |
| bit | 1 kB = 8,000 b | × 8,000 |
| kibibyte (binary) | 1 kB = 0.9765625 KiB | × 0.9765625 |
| mebibyte (binary) | 1 kB = 0.00095367 MiB | × 0.00095367 |
| gibibyte (binary) | 1 kB = 9.313226e-07 GiB | × 9.313226e-07 |
| tebibyte (binary) | 1 kB = 9.094947e-10 TiB | × 9.094947e-10 |