Both measure how often something repeats per unit time, but rpm counts full revolutions per minute while Hz counts cycles per second. To convert: rpm ÷ 60 = Hz. A motor spinning at 3,600 rpm runs at exactly 60 Hz.

Angular frequency ω (rad/s) and ordinary frequency f (Hz) are related by ω = 2π × f. Divide rad/s by 2π (≈ 6.2832) to get Hz. For example, 100 rad/s ≈ 15.92 Hz.

Healthy young adults typically hear from about 20 Hz to 20,000 Hz (20 kHz). Sensitivity decreases with age, especially above 4 kHz. Middle A (concert pitch) is exactly 440 Hz.

Divide BPM by 60 to get Hz. A song at 120 BPM has a beat frequency of exactly 2 Hz. Conversely, multiply Hz by 60 to get BPM — 1 Hz equals 60 BPM.