Your favorite FM station at 101.1 MHz is really a three-meter wave washing over your car antenna. Frequency and wavelength are two views of the same wave, linked by its speed: wavelength equals wave speed divided by frequency (λ = v / f), frequency equals speed divided by wavelength (f = v / λ), and speed equals their product (v = λ × f). Light always travels at 300 million m/s, so a higher frequency inevitably means a shorter wavelength — blue light's waves are visibly stubbier than red's.

This calculator runs any leg of the triangle. Choose Wavelength (λ = v / f), Frequency (f = v / λ), or Wave Speed (v = λ * f) in the Calculate dropdown, then enter the two knowns — the Wavelength (λ) box, the Frequency (f) box in hertz, the Wave Speed (v) box in m/s. The Computed Value box fills in the missing piece. A ham operator in Kansas checking the 20-meter band, for instance, picks Frequency, enters 20 for wavelength and 300,000,000 for wave speed, and reads 15 MHz — confirming the band plan before transmitting.

With the pre-filled defaults — Calculate Wavelength (λ = v / f), Wavelength (λ) 0.7795 m, Frequency (f) 440 Hz, Wave Speed (v) 343 m/s — the Wavelength Calculator returns Computed Value 0.7795. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.