Wavelength & Frequency Calculator
Instantly calculate relationships between frequency, wavelength, and energy. Explore the result on the interactive electromagnetic spectrum.
Frequency (f) to Wavelength (λ)
Wavelength (λ) to Frequency (f)
Energy (E) to Wavelength (λ)
λ = hc / E
Electromagnetic Spectrum
This chart visualizes the full range of electromagnetic waves, from long radio waves to short gamma rays. Your calculated result is marked with a vertical line, providing immediate context.
The Wavelength Formula
The relationship between wavelength, frequency, and wave speed is fundamental in physics. The formula to calculate wavelength is:
Wavelength (λ) = Wave Speed (v) / Frequency (f) Energy and Wavelength
The energy of a photon is directly proportional to its frequency and inversely proportional to its wavelength. This relationship is defined by the Planck–Einstein relation:
Energy (E) = Planck's Constant (h) * Frequency (f) or
Energy (E) = (Planck's Constant (h) * Speed of Light (c)) / Wavelength (λ) - Wavelength (λ): The distance over which the wave's shape repeats, measured in meters (m).
- Frequency (f): The number of wave crests that pass a point per second, measured in Hertz (Hz).
- Wave Speed (v): The speed at which the wave propagates. For electromagnetic waves, this is the speed of light (c), approximately 299,792,458 m/s.
- Energy (E): The energy of the wave, often measured in Joules (J) or electron-volts (eV).
Example 1: Wavelength of an FM Radio Station
Let's find the wavelength for an FM radio station broadcasting at 98.1 MHz.
- 1 Identify the knowns: Frequency (f) = 98.1 MHz, Wave Speed (v) = Speed of light (c).
- 2 Apply the formula:
λ = v / f - 3 Result: 3.06 meters. This is a typical wavelength for radio waves.
Example 2: Frequency of a Microwave Oven
A typical microwave oven operates at a wavelength of 12.2 cm.
- 1 Identify the knowns: Wavelength (λ) = 12.2 cm, Wave Speed (v) = Speed of light (c).
- 2 Apply the formula:
f = v / λ - 3 Result: 2.46 GHz.
What is the relationship between wavelength and energy?
Energy and wavelength are inversely related. Shorter wavelengths correspond to higher energy waves (like gamma rays), while longer wavelengths correspond to lower energy waves (like radio waves).
What is the wavelength of visible light?
Visible light for humans corresponds to a very narrow band of the electromagnetic spectrum, typically from about 380 nanometers (violet) to 750 nanometers (red).
Does the medium affect wavelength?
Yes. When a wave (like light) enters a different medium (like from air to water), its speed changes but its frequency remains constant. Since wavelength is dependent on speed (λ = v/f), a change in speed will cause a proportional change in wavelength.
Why is the speed of light the default wave speed?
This calculator is primarily designed for electromagnetic waves (light, radio, microwaves, etc.), which all travel at the speed of light in a vacuum. You can change this value to calculate the wavelength for other types of waves, such as sound in air (approx. 343 m/s).
