Wavelength Calculator
Calculate wavelength from frequency and wave speed.
Supports light (speed of light) and sound waves.
Shows results in meters, nanometers, and centimeters.
Wavelength is the distance between successive crests (or troughs) of a wave. It is directly related to frequency and wave speed through one of the most fundamental equations in physics.
Wavelength Formula:
λ = v / f
- λ (lambda) = Wavelength in meters
- v = Wave speed in m/s
- f = Frequency in Hz (cycles per second)
Equivalently: f = v / λ and v = f × λ
For electromagnetic waves (light, radio, X-rays) in vacuum: v = c = 299,792,458 m/s ≈ 3.0 × 10^8 m/s
Worked example — FM radio: FM station frequency: 101.5 MHz = 101,500,000 Hz Wavelength = 3.0 × 10^8 / 101,500,000 = 2.96 meters
This is why FM radio antennas are roughly 75 cm long (a quarter-wavelength dipole).
Worked example — visible light (green): Frequency: 540 THz = 5.40 × 10^14 Hz Wavelength = 3.0 × 10^8 / 5.40 × 10^14 = 5.56 × 10^-7 m = 556 nm
Electromagnetic spectrum reference:
| Type | Wavelength Range |
|---|---|
| AM radio | 100–1,000 m |
| FM radio | 2.5–3.5 m |
| Microwave | 1 mm–1 m |
| Infrared | 700 nm–1 mm |
| Visible light | 400–700 nm |
| UV | 10–400 nm |
| X-ray | 0.01–10 nm |
| Gamma | <0.01 nm |
Sound waves in air (20°C): v_sound = 343 m/s Middle C (261.6 Hz): λ = 343 / 261.6 = 1.31 meters
Energy and wavelength are inversely related: shorter wavelength = higher energy (Planck’s law: E = hf = hc/λ).