A frequency converter changes a rate of repetition between units — megahertz to gigahertz, or revolutions per minute to hertz. Frequency counts how many times something repeats each second, whether that is a processor clock, a radio wave, an engine's crankshaft or a heartbeat. This tool covers Hz, kHz, MHz, GHz, RPM and BPM.
The formula. Every value passes through the hertz — one cycle per second. The metric steps are decimal: 1 kHz = 1,000 Hz, 1 MHz = 1,000,000 Hz and 1 GHz = 1,000,000,000 Hz. The per-minute units simply divide by 60: 1 RPM = 1/60 Hz and 1 BPM = 1/60 Hz. Frequency is also the reciprocal of period, so f = 1 ÷ T — a 50 Hz mains supply has a 20 millisecond cycle.
Worked example. A 3.6 GHz processor runs 3,600,000,000 cycles per second, which is 3,600 MHz. An engine at 6,000 RPM is turning 6,000 ÷ 60 = 100 times per second, or 100 Hz. A resting heart rate of 60 BPM is exactly 1 Hz — one beat every second.
Where it's used. Processor and memory clocks are quoted in MHz and GHz; radio, Wi-Fi and mobile bands in MHz and GHz (2.4 GHz Wi-Fi is 2,400 MHz); mains electricity at 50 Hz or 60 Hz depending on the country; musical tempo in BPM; and engine and motor speeds in RPM. Audio sits in the same family — human hearing spans roughly 20 Hz to 20 kHz, and CD audio samples at 44.1 kHz.