By EnginStack Engineering Team | Verified by engineers, built on NIST metrology standards About →

Why Frequency Conversion Feels So Easy (and Where It Bites)

The hertz — cycles per second — was named in 1930 by the IEC in honor of Heinrich Hertz, who proved the existence of radio waves in 1887. The SI adopted it as the unit of frequency in 1960, and its SI-prefixed derivatives (kHz, MHz, GHz) are exact powers of ten by construction. This makes most frequency conversion trivial: moving between Hz, kHz, MHz, and GHz is decimal-point shifting, not multiplication by a constant. A 2.4 GHz Wi-Fi channel is 2,400,000,000 Hz. A 440 Hz tuning note is 0.44 kHz. Both are exact.

The trap is the crossover between cycles-per-second and revolutions-per-minute. A motor spinning at 3,600 RPM is not spinning at 3,600 Hz — it's spinning at 60 Hz, because each revolution is one cycle and each minute holds 60 seconds. A 60 Hz AC power line drives a 4-pole motor at exactly 1,800 RPM (synchronous speed). The Hz to RPM and RPM to Hz converters exist for this crossover, and the factor of 60 is exact — 1 RPM = 1/60 Hz. If you're converting audio frequencies (Hz to kHz), the frequency conversions in this hub are your pages. If you're converting motor speeds, the RPM pages are the ones that matter, and they link naturally to the time and speed families.

Hz to kHz

Audio & signal base pair

kHz to MHz

RF & broadcast pair

Hz to RPM

Motor speed crossover

MHz to GHz

Wireless & computing pair

What's on this page

Eight converters covering the frequency range from a heartbeat (1.2 Hz) to a 5 GHz Wi-Fi band — plus the RPM crossover that links frequency to rotating machinery. Every conversion here is exact: no measured constants, no rounding, no approximation. The kHz/MHz/GHz steps are powers of ten; the Hz↔RPM pair uses the exact factor of 60. If you're converting signal frequencies, the data storage hub has the related data-rate converters (Mbps, Gbps) for network speeds. If you're converting motor speeds, the speed hub covers the linear velocities those rotations produce.

Deep dive: read the Frequency Conversion Guide — the 440-Hz standard, the 50/60 Hz grid divide, and why the hertz is the easiest unit on this site except for the RPM crossover.