Prefixes like "kilo (k)", "mega (M)", and "giga (G)" used in digital data sizes originally represent powers of 10 (10³=1000 times, 10⁶=1,000,000 times, etc.). However, in computing, where binary is fundamental, these prefixes have sometimes been used to represent powers of 2 (2¹⁰=1024 times, 2²⁰=1,048,576 times, etc.), causing confusion.
To resolve this confusion, the IEC (International Electrotechnical Commission) standardized new prefixes to represent powers of 2. These are "kibi (Ki)", "mebi (Mi)", "gibi (Gi)", "tebi (Ti)", etc.
According to these standards:
kb (kilobit): 10³ bits = 1000 bitsKB (kilobyte): 10³ bytes = 1000 byteskib (kibibit): 2¹⁰ bits = 1024 bitsKiB (kibibyte): 2¹⁰ bytes = 1024 bytesIn other words, the prefix "k" correctly represents 1000 times, while "Ki" represents 1024 times. Also, lowercase "b" represents "bits", and uppercase "B" represents "bytes" (1 byte = 8 bits). However, in older systems or certain contexts, "KB" might still mean 1024 bytes, differing from the standard. Notably, storage capacities (HDD, SSD, etc.) are often calculated using 1000-based units, while memory capacities (RAM) typically use 1024-based units.