🔄 Converters
📡 📡 Frequency Converter: Hz, kHz, MHz, GHz Explained
Learn how to convert between frequency units: Hz, kHz, MHz, and GHz. Covers the frequency spectrum, period vs frequency, radio bands, audio frequencies, and CPU clock speeds.
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Frequency measures how many times a repeating event occurs per second — expressed in Hertz (Hz). From the 20 Hz lower limit of human hearing to the 5 GHz Wi-Fi bands, to the 3+ GHz clock speeds of modern CPUs, frequency spans many orders of magnitude in everyday technology. Converting between Hz, kHz, MHz, and GHz is straightforward since they're all powers of 1,000.
Frequency Units
- Hertz (Hz): 1 cycle per second — the SI base unit
- Kilohertz (kHz): 1,000 Hz — audio frequencies, AM radio
- Megahertz (MHz): 1,000,000 Hz — FM radio, older CPUs, Wi-Fi
- Gigahertz (GHz): 1,000,000,000 Hz — modern CPUs, 5 GHz Wi-Fi, microwave
- Terahertz (THz): 10¹² Hz — infrared light, experimental communications
Conversion Table
| Convert |
Formula |
Example |
| Hz → kHz | ÷ 1,000 | 5,000 Hz = 5 kHz |
| kHz → MHz | ÷ 1,000 | 1,500 kHz = 1.5 MHz |
| MHz → GHz | ÷ 1,000 | 3,600 MHz = 3.6 GHz |
| GHz → MHz | × 1,000 | 2.4 GHz = 2,400 MHz |
| Hz → GHz | ÷ 1,000,000,000 | 3,200,000,000 Hz = 3.2 GHz |
Frequency and Period
Frequency and period are inverses of each other:
Period (T) = 1 / Frequency (f) | Frequency = 1 / Period
- A 1 Hz signal repeats every 1 second
- A 50 Hz power grid signal repeats every 0.02 seconds (20 milliseconds)
- A 3 GHz CPU executes a cycle every 1/3,000,000,000 ≈ 0.33 nanoseconds
Frequency in Everyday Technology
| Technology |
Frequency Range |
| Human hearing | 20 Hz – 20 kHz |
| Mains electricity (US) | 60 Hz |
| Mains electricity (Europe) | 50 Hz |
| AM radio | 530 – 1,700 kHz |
| FM radio | 87.5 – 108 MHz |
| Wi-Fi 2.4 GHz band | 2.4 – 2.5 GHz |
| Wi-Fi 5 GHz band | 5.1 – 5.8 GHz |
| Modern CPUs | 3 – 6 GHz (boost) |
| 5G mobile networks | 600 MHz – 39 GHz |
Audio Frequencies
In music and audio engineering, frequency corresponds to pitch:
- A4 (concert pitch): 440 Hz
- Bass frequencies: 20–300 Hz
- Midrange: 300 Hz – 3 kHz (where most vocal intelligibility lives)
- Treble: 3–20 kHz
- CD audio sample rate: 44.1 kHz (captures up to 22.05 kHz per Nyquist theorem)
❓ Frequently Asked Questions
How do I convert GHz to MHz?▼
Multiply GHz by 1,000. 2.4 GHz = 2,400 MHz; 3.6 GHz = 3,600 MHz. To convert MHz to GHz: divide by 1,000. All frequency unit conversions are powers of 1,000: Hz → kHz → MHz → GHz → THz (each step divides or multiplies by 1,000).
What is the difference between Hz, kHz, MHz, and GHz?▼
All measure cycles per second, just at different scales. 1 kHz = 1,000 Hz, 1 MHz = 1,000,000 Hz, 1 GHz = 1,000,000,000 Hz. Use kHz for audio and AM radio, MHz for FM radio and older processors, GHz for modern CPUs and Wi-Fi. A 3.5 GHz CPU executes 3,500,000,000 clock cycles per second.
What frequency is human hearing?▼
Human hearing ranges from approximately 20 Hz to 20,000 Hz (20 kHz). The range narrows with age — adults over 40 typically can't hear above 15–16 kHz. Sounds below 20 Hz are infrasound (felt rather than heard); sounds above 20 kHz are ultrasound (used in medical imaging and dog whistles).
What is the relationship between frequency and period?▼
Period and frequency are mathematical inverses: Period (T) = 1/Frequency (f). A 50 Hz electrical signal has a period of 1/50 = 0.02 seconds (20 ms). A 440 Hz musical note has a period of 1/440 ≈ 2.27 ms. A 3 GHz CPU clock has a period of 1/3,000,000,000 ≈ 0.33 nanoseconds.
Why does Wi-Fi have 2.4 GHz and 5 GHz bands?▼
2.4 GHz travels farther and penetrates walls better but is more congested (shared with microwaves, Bluetooth). 5 GHz offers faster speeds and less congestion but shorter range. Wi-Fi 6E added 6 GHz. The higher the frequency, the shorter the wavelength and the less it penetrates obstacles — a fundamental physics trade-off between range and speed.