Frequency Calculator
Find the frequency of a wave or oscillation from its period, its wavelength or its angular frequency.
How to use the Frequency Calculator
- Choose the calculate from.
- Enter the period and pick its unit.
- Enter the wavelength and pick its unit.
- Choose the wave speed.
- Enter the custom wave speed and pick its unit.
- Enter the angular frequency.
- Press Calculate. The result updates automatically as you type, and you can switch the result unit at any time.
About the Frequency Calculator
Frequency counts how many times something repeats each second. It describes sound pitch (middle A is 440 Hz), household AC power (60 Hz in North America, 50 Hz in most other countries), radio stations (FM broadcasts around 88–108 MHz) and processor clocks (several GHz). Period is simply the inverse: the time one cycle takes.
For waves, frequency, wavelength and speed are linked. The speed depends on the medium, not the source, so a sound of a given pitch has a much longer wavelength in water than in air. Angular frequency, used in circuit analysis and oscillation equations, is 2π times the ordinary frequency; 60 Hz mains is about 377 rad/s.
Formula
f = 1 ÷ T
f = v ÷ λ
f = ω ÷ 2π
f is frequency in hertz (cycles per second), T the period in seconds, v the wave speed, λ the wavelength and ω the angular frequency in radians per second. Example: a period of 2 ms gives f = 1 ÷ 0.002 = 500 Hz.
Example calculation
Using the default values:
- Calculate from = Period (time per cycle)
- Period = 2 ms
the calculator returns:
- Frequency: 500 Hz
- Period: 0.002 s
- Angular frequency: 3,141.5927 rad/s
Frequently asked questions
How do I calculate frequency from period?
Divide 1 by the period in seconds. A period of 0.02 s gives 50 Hz.
What is the frequency of a sound with a 1 m wavelength?
In air at 20 °C, 343 ÷ 1 = 343 Hz.
What is the difference between Hz and rpm?
Both count cycles per unit time. 1 Hz = 60 rpm, so 3,000 rpm = 50 Hz.
Last updated: · Category: Science calculators