48Kb

48kB is a shorthand notation for 48 kilobytes, a unit of digital information equal to 48 divided by 1000 or 48,000 bytes in the decimal system, or 48 times 1024 (49,152) bytes in the binary system that is commonly used in computer memory calculations. The abbreviation “kB” follows the International System of Units, while “KiB” is used when referring to the binary prefix.

The term is frequently encountered in discussions of embedded systems, vintage computer hardware, and early video game cartridges, where total program and data size is constrained by limited flash or ROM capacity. For instance, certain microcontrollers use 48 kB pages of flash memory that can be independently erased, making 48 kB a convenient block size for firmware updates. In retro computing, some MS‑DOS applications were limited to a 48 kB maximum file size due to DOS 1.x and early hard disk controller limitations. The size is also a common benchmark for benchmarking disk transfer speeds, especially in directories with many small files.

Because 48 kB is small but nontrivial, it remains a useful reference point when optimizing code for size, configuring embedded storage, or studying the storage constraints of historical computing environments.