Hertz (Hz) - Unit Information & Conversion
🔄 Quick Convert Hertz
What is a Hertz?
The hertz (Hz) is the SI unit of frequency, equal to one cycle per second. Named after Heinrich Hertz, it measures oscillations, waves, vibrations, and periodic events in physics, electronics, and everyday phenomena.
History of the Hertz
Named after German physicist Heinrich Hertz (1857-1894), who first conclusively proved the existence of electromagnetic waves. Adopted as the SI unit of frequency in 1960, replacing "cycles per second" (cps).
Quick Answer
What is a Hertz? A hertz (Hz) is the SI unit of frequency equal to one cycle, oscillation, or occurrence per second. It measures how often a repeating event happens. Used for AC power (50/60 Hz), sound waves, radio waves, and any periodic phenomenon. Higher values use kilohertz (kHz), megahertz (MHz), or gigahertz (GHz). Use our frequency converter to convert Hz to other units instantly.
Definition
1 Hz = 1 cycle per second = 1/second = s⁻¹
Metric prefixes:
- 1,000 Hz = 1 kHz (kilohertz)
- 1,000,000 Hz = 1 MHz (megahertz)
- 1,000,000,000 Hz = 1 GHz (gigahertz)
Common Uses
AC Power: 50 Hz (Europe/Asia) or 60 Hz (Americas) - frequency of alternating current electricity. Audio: 20 Hz - 20,000 Hz (20 kHz) is the human hearing range. Display Refresh: Monitor and TV refresh rates (60 Hz, 120 Hz, 144 Hz, 240 Hz). Vibrations: Engine vibrations, seismic waves, mechanical oscillations measured in Hz.
Real-World Examples
Electrical Power Frequencies
- North America, Japan (East): 60 Hz standard
- Europe, Asia, Africa, Australia: 50 Hz standard
- Japan (West): 60 Hz (Tokyo) vs 50 Hz (Osaka) - dual system
- Aircraft power: 400 Hz (more compact transformers)
Audio Frequencies
- Sub-bass: 20-60 Hz (felt more than heard)
- Bass: 60-250 Hz (kick drums, bass guitars)
- Midrange: 250-2000 Hz (vocals, most instruments)
- Treble: 2-20 kHz (cymbals, high notes)
- Musical note A4: 440 Hz (standard tuning pitch)
- Middle C: 261.63 Hz
Display Refresh Rates
- Standard monitors: 60 Hz (16.67 ms per frame)
- Gaming monitors: 144 Hz, 165 Hz, 240 Hz, 360 Hz
- Cinema: 24 Hz (film), 48 Hz (HFR cinema)
- TV (PAL): 50 Hz interlaced
- TV (NTSC): 60 Hz interlaced
Natural Phenomena
- Human heartbeat: ~1.2 Hz (72 BPM)
- Walking pace: ~2 Hz (2 steps per second)
- Earthquake waves: 0.01-10 Hz
- Ocean waves: 0.05-0.5 Hz
Hertz Conversion Formulas
To Millihertz:
To Kilohertz:
To Megahertz:
To Gigahertz:
To Terahertz:
To Revolutions per Minute:
To Revolutions per Second:
To Beats per Minute:
To Cycles per Second:
To Radians per Second:
Frequently Asked Questions
Formula: kHz = Hz ÷ 1,000 Examples:
- 1,000 Hz = 1 kHz
- 440 Hz = 0.44 kHz (A4 musical note)
- 20,000 Hz = 20 kHz (upper hearing limit)
- 100 Hz = 0.1 kHz Hz to kHz converter →
Convert Hertz
Need to convert Hertz to other frequency units? Use our conversion tool.