International System of Units (SI) Measures Used in Computer Science

NIST Reference

Memory Storage in bytes
Factor Symbol Name Conversion
1 byte byte 1 byte = 8 bits
2^10 kB kilobyte 1 kB = 1024 bytes
2^20 MB megabyte 1 MB = 1024 kilobytes
2^30 GB gigabyte 1 GB = 1024 megabytes
2^40 TB terabyte 1 TB = 1024 gigabytes
Timing in Seconds
Factor Symbol Name Conversion
10^-3 ms millisecond 1000 ms = 1 sec
10^-6 µs (greek lowercase Mu) microsecond 1000 µs = 1 ms
1 million µs = 1 sec
10^-9 ns nanosecond 1000 ns = 1 µs
1 billion ns = 1 sec
10^-12 ps picosecond 1000 ps = 1 ns
1 trillion ps = 1 sec
CPU clock rate in hertz (Hz)
10^3 kHz kilohertz kHz = 1000 Hz
10^6 mHz megahertz mHz = 1000 kHz
10^9 GHz gigahertz GHz = 1000 mHz
10^12 THz terahertz THz = 1000 GHz