Frequency converter

Hertz is the reference unit for this converter, defined as one cycle per second. Kilohertz, megahertz, gigahertz and terahertz scale up by powers of a thousand, while millihertz scales down the same way. A few units carry different names for the same mathematical idea: cycle per second (cps), revolution per second (rps) and frame per second (fps) are all numerically identical to hertz, since each describes one repeating event per second.

The featured pair is megahertz to hertz: Hz = MHz × 1,000,000. Reversing it means multiplying by 0.000001 (1×10⁻⁶) instead, or simply dividing by a million.

A 3.5 GHz processor clock converts to 3.5 × 1,000 = 3,500 MHz. An engine idling at 800 rpm converts to 800 × 0.016666667 ≈ 13.33 Hz, since revolutions per minute must first be divided by 60 to reach a per-second rate.

Electronics and telecommunications default to hertz and its upward multiples: radio stations, Wi-Fi bands and CPU clock speeds are all specified in kHz, MHz or GHz. Mechanical and automotive engineering prefers rpm for anything rotating, from engine crankshafts to drill bits, because counting whole revolutions per minute is more intuitive than counting cycles per second for a slowly turning shaft. Musicians and metronomes use beats per minute (bpm) for tempo, which is mathematically the same divide-by-60 relationship as rpm even though the two fields rarely think of themselves as using related units. Angular velocity in physics and robotics is usually given in radians per second instead, since that's the form calculus-based motion equations expect.

The easiest error in this category is forgetting the factor of 60 between rpm and Hz: an electric motor rated at 1,800 rpm runs at 30 Hz, not 1,800 Hz, because rpm counts revolutions per minute while Hz counts cycles per second. A second point of confusion is the older unit "cps" (cycles per second): it's simply the earlier name for hertz and converts 1:1, so any vintage equipment, textbook or manual using cps can be read as hertz with no math required at all.

Degree per second and radian per second describe the same angular motion in two different full-circle conventions: 360 degrees per second and 2π (about 6.283) radians per second both equal exactly 1 Hz, since both describe one complete rotation happening once every second. Radians are generally preferred in engineering calculations because they simplify the math of circular motion, while degrees per second remain more intuitive for visualizing how fast something is actually spinning.