Common frequency conversions

Value	Equivalent
1 kHz	1,000 Hz
1 MHz	1,000 kHz = 1,000,000 Hz
1 GHz	1,000 MHz = 10⁹ Hz
1 THz	1,000 GHz = 10¹² Hz
60 RPM	1 Hz = 1 rev/s
3,600 RPM	60 Hz

How frequency conversion works

All conversions pass through Hertz (Hz) as the base unit. 1 Hz means one cycle per second. SI prefixes apply: kHz = 10³ Hz, MHz = 10⁶ Hz, GHz = 10⁹ Hz, THz = 10¹² Hz.

RPM (revolutions per minute) converts to Hz by dividing by 60. For example, 3,000 RPM = 50 Hz.

Frequency in audio

The human hearing range spans approximately 20 Hz to 20,000 Hz (20 kHz), though high-frequency sensitivity declines significantly with age (a process called presbycusis). Each musical octave doubles the frequency: A4 = 440 Hz, A5 = 880 Hz, A3 = 220 Hz. The frequency range is divided into sub-bass (20–60 Hz), bass (60–250 Hz), midrange (250 Hz–4 kHz), presence (4–6 kHz), and brilliance/air (6–20 kHz).

Frequency in the electromagnetic spectrum

Band	Frequency range	Example uses
AM radio	535–1,605 kHz	Amplitude-modulated broadcast radio
FM radio	88–108 MHz	Frequency-modulated broadcast radio
WiFi 2.4 GHz	2,400–2,484 MHz	802.11b/g/n wireless LAN
WiFi 5 GHz	5,150–5,850 MHz	802.11a/ac/ax wireless LAN
Visible light	~400–750 THz	Violet (750 THz) to red (400 THz)

Angular frequency

Angular frequency ω (omega) is related to Hz by ω = 2πf, measured in radians per second (rad/s). It is the preferred form in physics equations because it eliminates the 2π factors that appear constantly when working with sinusoidal signals. For example, a 60 Hz power grid has an angular frequency of ω = 2π × 60 ≈ 377 rad/s.