Frequency
Hz, kHz, MHz, GHz
About This Calculator
Frequency measures how many cycles of a repeating event occur per second, expressed in hertz (Hz). It is fundamental to electronics, communications, acoustics, and physics. Radio stations broadcast at MHz frequencies; WiFi and 5G operate at GHz; the human voice spans 85-255 Hz; electrical power runs at 50 or 60 Hz.
Formula
1 kilohertz (kHz) = 1,000 Hz
1 megahertz (MHz) = 1,000,000 Hz
1 gigahertz (GHz) = 1,000,000,000 Hz
Period (sec) = 1 / Frequency (Hz) → T = 1/f
Example Calculation
Convert 2.4 GHz WiFi frequency to MHz and Hz, and find period.
- MHz = 2.4 × 1,000 = 2,400 MHz
- Hz = 2.4 × 1,000,000,000 = 2,400,000,000 Hz
- Period = 1 / 2,400,000,000 = 0.000000000417 sec ≈ 0.42 nanoseconds
2.4 GHz = 2,400 MHz = 2.4×10⁹ Hz; Period ≈ 0.42 ns
Frequency Reference Guide
| Application | Frequency | Band |
|---|---|---|
| Human hearing range | 20 Hz – 20 kHz | Audio |
| AM radio | 530 – 1700 kHz | Medium wave |
| FM radio | 88 – 108 MHz | VHF |
| WiFi 2.4 GHz | 2,400 – 2,500 MHz | UHF/microwave |
| WiFi 5 GHz | 5,150 – 5,850 MHz | SHF |
| 5G mid-band | 2.5 – 3.7 GHz | SHF |
| CPU clocks | 2 – 5 GHz | — |
| Visible light | 430 – 770 THz | Optical |
Frequently Asked Questions
What is the relationship between frequency and wavelength?
Speed = frequency × wavelength. For electromagnetic waves (light, radio): c = f × λ, where c = 299,792,458 m/s. At 100 MHz (FM radio), wavelength = 3×10⁸/10⁸ = 3 meters. Higher frequency → shorter wavelength.
Why is 5 GHz WiFi faster than 2.4 GHz?
Higher frequency (5 GHz) can carry more data per second (higher bandwidth) but has shorter range and worse penetration through walls. 2.4 GHz travels farther and penetrates better but is more congested. Modern WiFi 6/6E uses both bands plus 6 GHz.
What is the difference between Hz and bps?
Hertz measures cycles per second of a physical signal. Bits per second (bps) measures data throughput. They relate through encoding: a 100 MHz signal can carry more than 100 Mbps depending on the modulation scheme (how many bits per cycle). WiFi can encode 6-12 bits per Hz with advanced modulation.
What frequency is AC power?
The US and most of the Americas use 60 Hz AC power; Europe, Asia, and Africa use 50 Hz. This is why some appliances (especially motors and older electronics) designed for one system don't work properly on the other. The frequency determines motor speeds and can affect timekeeping in older clocks.