How to use the Frequency Calculator
Every periodic wave — a sound wave, a light wave, a radio signal, a wave on a string — obeys the same relationship between how fast it travels, how far apart its repeating crests are, and how often a crest passes a fixed point. This calculator applies that relationship, the wave equation, to solve for whichever one of the three quantities (frequency, wavelength, or wave speed) you don't already know, and reports the wave's period alongside it.
The wave equation: v = f × λ
The wave equation states that wave speed (v) equals frequency (f) times wavelength (λ, the Greek letter lambda): v = f × λ. Frequency is measured in hertz (Hz, cycles per second), wavelength in meters, and speed in meters per second. Rearranging the same equation gives the other two forms used here: f = v / λ to solve for frequency, and λ = v / f to solve for wavelength. Pick "Solve for" above, enter the other two known values with their units, and the calculator converts everything to consistent SI units before computing.
Period and angular frequency
Frequency and period are reciprocals of each other: T = 1 / f. If a wave oscillates at 1000 Hz, one full cycle takes T = 1/1000 = 0.001 second. Some fields — rotational motion, AC circuits, oscillators — use angular frequency instead, ω = 2π × f, measured in radians per second rather than cycles per second; multiply the frequency shown here by 2π to get it. For electromagnetic waves (light, radio, microwaves) traveling in a vacuum, use the speed of light preset (c ≈ 2.998 × 10⁸ m/s) as the wave speed; for sound in air at room temperature, about 343 m/s is a standard approximation.