Wavelength & Frequency Calculator
Calculate wavelength, frequency, or wave speed using λ = v/f. Supports electromagnetic waves, sound, and custom media.
Results
What is it?
The wave equation λ = v/f (wavelength = wave speed / frequency) relates the three fundamental properties of any periodic wave. Visible light occupies 400–700 nm; the full EM spectrum ranges from radio waves (km) to gamma rays (pm). Human hearing spans 20 Hz–20 kHz; middle A (concert pitch) is 440 Hz with λ ≈ 0.78 m in air.
How to use
Select the medium to auto-fill the wave speed, or choose "Custom speed" and enter your own value. Then select whether you want to solve for wavelength or frequency, and enter the known quantity.
Example scenario
What is the wavelength of 440 Hz (concert A) sound in air? Select "Sound in air (343 m/s)", "Solve for Wavelength", and enter frequency = 440 Hz. λ = 343 / 440 ≈ 0.7795 m (about 78 cm). In water (1480 m/s), the same note would have λ ≈ 3.36 m.
Pro tip
EM spectrum reference: Radio > 1 m | Microwave 1 mm–1 m | Infrared 700 nm–1 mm | Visible 400–700 nm | UV 10–400 nm | X-ray 0.01–10 nm | Gamma < 0.01 nm. The speed of light in a medium is c/n where n is the refractive index — glass has n ≈ 1.5, so light travels at ≈ 2×10⁸ m/s through it.