Frequency Converter — Convert Hz, kHz, MHz, GHz & THz
Our free online frequency converter provides instant, accurate conversion between all standard frequency units: Hertz (Hz), Kilohertz (kHz), Megahertz (MHz), Gigahertz (GHz), and Terahertz (THz). Whether you're working with audio frequencies, radio bands, CPU clock speeds, or electromagnetic spectrum calculations, this tool delivers precise results with a comprehensive reference guide.
What is Frequency?
Frequency is the number of complete cycles (oscillations) of a periodic wave that occur per unit time. It measures how often a repeating event occurs per second. The SI unit of frequency is the Hertz (Hz), named after German physicist Heinrich Hertz who first proved the existence of electromagnetic waves in 1887. One Hertz means one cycle per second.
Frequency is fundamental to virtually every field of science and technology: sound (audio frequencies), light (optical frequencies), radio communications (RF), computing (clock speeds), music (pitch), medicine (ultrasound), and telecommunications (carrier waves). The higher the frequency, the more energy the wave carries and the shorter its wavelength.
Frequency Units Explained
| Unit | Symbol | Equivalent in Hz | Common Use |
|---|---|---|---|
| Hertz | Hz | 1 | Audio bass, power grid (50/60 Hz) |
| Kilohertz | kHz | 1,000 | Audio sampling, AM radio |
| Megahertz | MHz | 1,000,000 | FM radio, TV, older CPUs |
| Gigahertz | GHz | 1,000,000,000 | Wi-Fi, CPUs, 5G, microwave |
| Terahertz | THz | 1,000,000,000,000 | Imaging, spectroscopy, 6G research |
The Electromagnetic Spectrum
The electromagnetic spectrum spans an enormous range of frequencies, from extremely low frequency (ELF) radio waves at 3 Hz to gamma rays above 10¹⁹ Hz. Here's how frequency bands map to everyday technologies:
| Band | Frequency Range | Applications |
|---|---|---|
| ELF / VLF | 3 Hz – 30 kHz | Submarine comms, power grid |
| LF / MF | 30 kHz – 3 MHz | AM radio, navigation beacons |
| HF | 3 MHz – 30 MHz | Shortwave radio, amateur radio |
| VHF | 30 MHz – 300 MHz | FM radio, TV, aviation |
| UHF | 300 MHz – 3 GHz | TV, 4G/LTE, GPS, Wi-Fi 2.4 GHz |
| SHF (Microwave) | 3 GHz – 30 GHz | Wi-Fi 5/6 GHz, 5G, radar, satellite |
| EHF (mmWave) | 30 GHz – 300 GHz | 5G mmWave, astronomy, security imaging |
| Infrared | 300 GHz – 430 THz | Remote controls, thermal imaging |
| Visible Light | 430 THz – 770 THz | Human vision, fiber optics |
Audio Frequencies
Sound waves that humans can hear range from approximately 20 Hz to 20,000 Hz (20 kHz). Understanding audio frequencies is essential for music production, sound engineering, and hearing health:
- Sub-bass (20–60 Hz): Felt more than heard — rumbling bass, earthquakes, organ pedal notes
- Bass (60–250 Hz): Kick drums, bass guitar, male speaking voice fundamentals
- Low Midrange (250–500 Hz): Body of most instruments, warmth in vocals
- Midrange (500 Hz–2 kHz): Most speech intelligibility, guitar presence
- Upper Midrange (2–4 kHz): Vocal clarity, ear sensitivity peak, harshness zone
- Presence (4–6 kHz): Definition, edge of sounds, consonant clarity
- Brilliance (6–20 kHz): Sparkle, air, cymbals, sibilance in vocals
Radio Bands Reference
| Service | Frequency | Converted |
|---|---|---|
| AM Radio | 540–1600 kHz | 0.54–1.6 MHz |
| FM Radio | 88–108 MHz | 88,000–108,000 kHz |
| Wi-Fi 2.4 GHz | 2.4 GHz | 2,400 MHz |
| Wi-Fi 5 GHz | 5 GHz | 5,000 MHz |
| 5G Sub-6 | 3.5 GHz | 3,500 MHz |
| 5G mmWave | 28–39 GHz | 28,000–39,000 MHz |
| GPS L1 | 1.57542 GHz | 1,575.42 MHz |
| Bluetooth | 2.402–2.48 GHz | 2,402–2,480 MHz |
CPU Clock Speeds
Modern processor speeds are measured in Gigahertz, representing billions of clock cycles per second. Here are some historical and current reference points:
- Intel 8086 (1978): 5–10 MHz = 5,000,000–10,000,000 Hz
- Intel Pentium (1993): 60–66 MHz = 60,000–66,000 kHz
- Intel Pentium 4 (2004): 3.8 GHz = 3,800 MHz
- Modern desktop CPUs (2026): 4.0–5.8 GHz = 4,000–5,800 MHz
- Boost clocks (gaming): Up to 6.0 GHz = 6,000,000 kHz
Frequency and Wavelength Relationship
Frequency (f) and wavelength (λ) are inversely related through the speed of propagation (c for electromagnetic waves in vacuum): λ = c / f, where c = 299,792,458 m/s (speed of light). For example, FM radio at 100 MHz has a wavelength of about 3 meters, while Wi-Fi at 5 GHz has a wavelength of about 6 cm. This relationship explains why higher frequencies have shorter range but can carry more data.
Frequently Asked Questions (FAQ)
1. How do you convert Hz to kHz?
Divide the Hertz value by 1,000 to get Kilohertz. For example, 44,100 Hz ÷ 1,000 = 44.1 kHz (the standard CD audio sampling rate). Conversely, multiply kHz by 1,000 to get Hz.
2. What is the difference between MHz and GHz?
1 GHz (Gigahertz) = 1,000 MHz (Megahertz) = 1,000,000 kHz = 1,000,000,000 Hz. GHz is used for modern CPU speeds, Wi-Fi frequencies, and microwave communications. MHz is common for FM radio and older electronics.
3. What frequency range can humans hear?
The human ear typically perceives frequencies between 20 Hz and 20,000 Hz (20 kHz). Hearing sensitivity peaks around 2–5 kHz. With age, the upper limit decreases — most adults over 40 can't hear above 15 kHz. Below 20 Hz is infrasound; above 20 kHz is ultrasound.
4. What is Terahertz (THz) radiation?
Terahertz radiation (0.1–10 THz) lies between infrared and microwave in the electromagnetic spectrum. It penetrates clothing and packaging but is non-ionizing (safe). Applications include airport security scanners, quality control, spectroscopy, and emerging 6G wireless research.
5. What frequency is FM radio?
FM radio broadcasts in the 88–108 MHz range (VHF Band II). Each station occupies about 200 kHz bandwidth. For example, a station at "98.5 FM" operates at 98.5 MHz = 98,500 kHz = 98,500,000 Hz.
6. What frequency does Wi-Fi use?
Wi-Fi uses 2.4 GHz (longer range, more interference) and 5 GHz (faster, shorter range) bands. Wi-Fi 6E and Wi-Fi 7 also use 6 GHz. The 2.4 GHz band has only 3 non-overlapping channels, while 5 GHz offers 25+, reducing congestion.
7. How is CPU clock speed measured?
CPU clock speed is measured in GHz (billions of cycles per second). A 5 GHz CPU executes 5 billion clock cycles each second. However, clock speed alone doesn't determine performance — architecture, IPC (instructions per cycle), and core count also matter significantly.
8. What is the relationship between frequency and wavelength?
They are inversely proportional: λ = c / f. Higher frequency means shorter wavelength. A 1 GHz signal has a wavelength of 30 cm; a 100 GHz signal has a wavelength of 3 mm. This is why 5G mmWave (high frequency) has short range but high bandwidth capacity.