A frequency converter with period and wavelength built in
This frequency converter changes a value between hertz, kilohertz, megahertz, gigahertz and terahertz, rotation and tempo units (rpm and bpm) and angular units (radians per second and degrees per second). Type a frequency and you see every unit at once, with the exact formula.
It also answers the next question you usually have: below the result, a panel shows the period of one cycle, the wavelength of a radio wave at that frequency and the wavelength of a sound wave in air. That makes it useful for electronics students, radio and Wi-Fi hobbyists, musicians, motor and fan specifications, and anyone comparing 50 Hz and 60 Hz equipment.
How to use the Frequency Converter
- Type a frequency in the Value box — for example 50, 2.4 or 3000.
- Choose its unit in From: Hz, kHz, MHz, GHz, THz, rpm, bpm, rad/s or °/s.
- Choose the unit you want in To, or use the round swap button to reverse.
- Read the result and the formula, then check the Period and wavelength at this frequency panel for T = 1 / f and λ = c / f.
- Use Precision and Copy as needed, scan the list of every frequency unit, or tap a quick conversion such as “60 Hz → rpm”.
Frequency Converter features
SI prefixes from Hz to THz
Move between hertz and its multiples without counting zeros.
Rotation and tempo
rpm for motors, fans and drives; bpm for music and heart rate — both are cycles per minute.
Angular frequency
Radians per second (ω = 2πf) and degrees per second for physics and control engineering.
Period shown automatically
One cycle at 50 Hz lasts 20 ms; at 2.4 GHz about 0.42 ns — displayed with sensible units.
Radio and sound wavelengths
See λ = c / f for electromagnetic waves and the wavelength of sound in air at 20 °C.
Frequency units and formulas
One hertz is one cycle per second. The unit honours Heinrich Hertz, who first demonstrated radio waves, and became the official SI name in 1960, replacing “cycles per second”. Revolutions or beats per minute are simply cycles per minute, so 1 Hz = 60 rpm = 60 bpm. Angular frequency counts radians instead of cycles; one cycle is 2π radians, so ω = 2πf.
| Unit | Value in hertz | Typical use |
|---|---|---|
| Kilohertz (kHz) | 1,000 | Audio, AM radio |
| Megahertz (MHz) | 1,000,000 | FM radio, older processors |
| Gigahertz (GHz) | 10⁹ | CPUs, Wi-Fi, mobile networks |
| Terahertz (THz) | 10¹² | Infrared and visible light |
| Revolutions per minute (rpm) | 1/60 | Motors, engines, fans, hard drives |
| Beats per minute (bpm) | 1/60 | Music tempo, heart rate |
| Radians per second (rad/s) | 1/(2π) ≈ 0.159155 | Physics, control systems |
| Degrees per second (°/s) | 1/360 | Gyroscopes, motion sensors |
Worked examples
Hz to rpm — multiply by 60. Mains electricity is 50 Hz in India, the UK and most of Europe, and 60 Hz in the US and Canada. A two-pole motor has a synchronous speed of 50 × 60 = 3,000 rpm on 50 Hz, or 3,600 rpm on 60 Hz; real induction motors run a little slower because of slip.
rpm to Hz — divide by 60. A fan at 1,500 rpm turns 25 times a second.
Hz to rad/s — multiply by 2π. 50 Hz is 314.16 rad/s, the ω that appears in AC circuit formulas.
Frequency to period — T = 1 / f. At 50 Hz one cycle lasts 1/50 = 0.02 s = 20 ms. A 3 GHz processor clock ticks every 0.333 ns. The time converter helps if you need the period in other units.
Frequency to wavelength — λ = c / f. Wi-Fi at 2.4 GHz has a wavelength of 299,792,458 ÷ 2.4 × 10⁹ = 0.1249 m, about 12.5 cm. The note A at 440 Hz has a sound wavelength in air of 343 ÷ 440 = 0.78 m.
Frequencies you meet every day
- Concert pitch: the A above middle C is standardised at 440 Hz. Try it with the tone generator.
- Heart rate and tempo: 60 bpm is exactly 1 Hz; a brisk 120 bpm song is 2 Hz. Find a song’s tempo with the BPM tapper.
- FM radio broadcasts between about 87.5 and 108 MHz in most countries, so 98.3 FM means 98.3 MHz.
- Wi-Fi uses bands around 2.4 GHz, 5 GHz and, with newer routers, 6 GHz.
- Japan is split: the east runs its grid at 50 Hz and the west at 60 Hz.
Common frequency conversions
| From | To |
|---|---|
| 1 Hz | 60 rpm |
| 50 Hz | 3,000 rpm |
| 60 Hz | 3,600 rpm |
| 1,000 rpm | 16.66666667 Hz |
| 1 Hz | 6.283185307 rad/s |
| 1 rpm | 0.1047197551 rad/s |
| 1 kHz | 1,000 Hz |
| 1 MHz | 1,000 kHz |
| 2.4 GHz | 2,400 MHz |
| 1 GHz | 1,000,000,000 Hz |
| 120 bpm | 2 Hz |
| 360 °/s | 60 rpm |
Frequency Converter FAQ
How do I convert Hz to rpm?
Multiply by 60, because rpm counts cycles per minute and hertz counts cycles per second. For example, 25 Hz × 60 = 1,500 rpm.
How do I convert rpm to Hz?
Divide by 60. A hard drive spinning at 7,200 rpm turns 120 times per second, which is 120 Hz.
What is the relationship between frequency and period?
They are reciprocals: period T = 1 / f and f = 1 / T. The frequency converter shows the period for any value you enter.
How do I convert Hz to rad/s?
Multiply by 2π (about 6.2832). 1 Hz = 6.2832 rad/s and 60 Hz = 376.99 rad/s.
How many MHz are in a GHz?
One gigahertz is 1,000 megahertz, and one megahertz is 1,000 kilohertz.
How do I find wavelength from frequency?
Divide the wave speed by the frequency. For radio and light use the speed of light, 299,792,458 m/s; for sound in air at room temperature use about 343 m/s.