Frequency Converter
Convert between hertz, kilohertz, megahertz, gigahertz, RPM, and more frequency units.
Each step along the axis is ten times the one before — the frequency units span 14 orders of magnitude, so a straight scale would bunch almost all of them at one end.
Instant insight
That is about the same as one beat per second
1 hertz — A resting pulse is around 1 Hz.
Anchors like this are the quickest way to catch an answer that is out by a factor of ten.
Frequency and wavelength are inversely related
Double the frequency and the wavelength halves, for a given wave speed — which is why the same frequency behaves differently in air and in water.
Check which wave speed a figure assumes: light and sound differ by a factor of nearly a million.
Check the direction of the conversion
Going from hertz to kilohertz, the number should get bigger if the new unit is smaller, and smaller if it is bigger.
If it moved the wrong way, the factor has been applied upside down — the most common conversion error there is.
Worked out in your browser — nothing is sent anywhere. Comparison figures are approximate.
Common conversions
Quick Reference — 1 unit = ? Kilohertz (kHz)
| Unit | Value |
|---|---|
| Hertz (Hz) | 0.001 |
| Kilohertz (kHz) | 1 |
| Megahertz (MHz) | 1000 |
| Gigahertz (GHz) | 1000000 |
| Terahertz (THz) | 1000000000 |
| RPM (rev/min) | 0.00001666666667 |
| RPS (rev/s) | 0.001 |
| Radians per Second (rad/s) | 0.0001591549431 |
Formula
Multiply by (from factor / to factor)
Everyday Uses
Music and audio
A440 tuning, 20 Hz–20 kHz hearing range, sample rates in kHz — convert frequencies across the audio world.
Processor speeds
MHz versus GHz across spec sheets — convert to compare chips, radios, and clock speeds meaningfully.
Radio bands
FM in MHz, shortwave in kHz, WiFi in GHz — translate between bands when working with radios and antennas.
Physics and RPM
Convert Hz to RPM and back for motors, centrifuges, and rotating machinery.
Musical pitch
Convert between hertz and kilohertz when tuning instruments or reading audio equipment specifications.
Radio and Wi-Fi bands
Move between MHz and GHz when comparing router bands or radio allocations.
Frequently Asked Questions
What is frequency (hertz) and how do the unit prefixes relate?
Frequency measures how many complete cycles occur per second. 1 hertz (Hz) = 1 cycle per second. Unit scale: 1 kHz = 1,000 Hz; 1 MHz = 1,000,000 Hz; 1 GHz = 1,000,000,000 Hz; 1 THz = 10¹² Hz. The relationship to period (time per cycle): f = 1/T. A 50 Hz power grid completes one AC cycle every 20 ms; a 4 GHz CPU processes 4 billion clock cycles per second (each cycle takes 0.25 ns).
What frequencies does the human ear hear, and how does sound frequency relate to pitch?
Human hearing range: approximately 20 Hz–20,000 Hz (20 kHz), though the upper limit decreases with age. Below 20 Hz = infrasound (felt not heard — earthquakes, deep bass); above 20 kHz = ultrasound (used in medical imaging, animal communication, dog whistles). Musical reference: middle A = 440 Hz (international concert pitch); middle C = 261.63 Hz; the lowest note of a piano = 27.5 Hz; the highest = 4,186 Hz. Each octave doubles the frequency.
What are the main radio frequency bands and their uses?
Radio frequency spectrum: AM radio: 530–1,700 kHz. FM radio: 87.5–108 MHz. VHF TV: 54–216 MHz. UHF TV: 470–890 MHz. Wi-Fi 2.4 GHz: 2,400–2,484 MHz. Wi-Fi 5 GHz: 5,150–5,850 MHz. Wi-Fi 6E / Wi-Fi 7: 6 GHz band. 4G LTE: 700 MHz–2.6 GHz. 5G sub-6: 600 MHz–6 GHz. 5G mmWave: 24–100 GHz. Bluetooth: 2.4 GHz. GPS: 1,575.42 MHz (L1 band). Microwave ovens: 2,450 MHz (2.45 GHz) — same band as Wi-Fi, which is why microwaves can interfere with 2.4 GHz Wi-Fi.
What is the difference between frequency and RPM, and how do you convert them?
RPM (revolutions per minute) measures rotational speed. Frequency (Hz = rev/s) measures the same thing per second. Conversion: Hz = RPM ÷ 60; RPM = Hz × 60. Example: a 3,000 RPM engine = 3,000 ÷ 60 = 50 Hz. Angular velocity in rad/s: ω = 2π × f = 2π × RPM/60. Example: 1,500 RPM = 25 Hz = 157 rad/s. Car engines idle at ~700–900 RPM; redline at 5,000–8,000 RPM. Hard drives spin at 5,400 or 7,200 RPM (90–120 Hz).
What is the frequency of visible light, X-rays, and other electromagnetic radiation?
The electromagnetic spectrum spans an enormous frequency range: Radio waves: 3 Hz–300 GHz. Microwaves: 300 MHz–300 GHz. Infrared: 300 GHz–430 THz. Visible light: 430–770 THz (wavelength 400–700 nm). Red: ~430 THz; violet: ~750 THz. Ultraviolet: 750 THz–30 PHz. X-rays: 30 PHz–30 EHz. Gamma rays: >30 EHz. Higher frequency = higher energy (E = hf, where h is Planck's constant). This is why X-rays and gamma rays are ionising radiation — they carry enough energy to break chemical bonds.