Wavelength Frequency Calculator
Convert between wavelength and frequency of a wave.
343 for sound in air, 299792458 for light
Results update as you type.
How it works
Every wave links its frequency and wavelength through its speed, and this calculator converts between the two for light, sound, radio, or any wave. You enter either the frequency or the wavelength, select which one you provided, and give the wave speed, and it returns the missing quantity. The governing relationship is one of the most fundamental in physics: wave speed equals frequency times wavelength. So if you know the speed and the frequency, the wavelength is speed divided by frequency; if you know the wavelength instead, the frequency is speed divided by wavelength. The wave speed depends on the type of wave and the medium: light and other electromagnetic waves travel at about 299,792,458 meters per second in a vacuum, while sound travels at roughly 343 meters per second in air at room temperature and faster in water or solids. This conversion is essential in acoustics, optics, radio and antenna design, spectroscopy, and physics education, where you routinely need to switch between how often a wave oscillates and how long each cycle is in space. High frequency means short wavelength and vice versa, since their product is fixed by the speed. Enter the known value, its type, and the wave speed to convert between wavelength and frequency.
v = f · λ → λ = v / f, f = v / λ
For any wave, the wave speed equals the frequency times the wavelength. Rearranging, the wavelength is the wave speed divided by the frequency, and the frequency is the wave speed divided by the wavelength. You supply one of the two along with the wave speed, and the calculator finds the other using this fundamental wave relationship.
Source:Wave physics
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter known value, this value is and wave speed.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Wavelength updates instantly as you type — no button to press.
Frequently asked questions
How do you convert frequency to wavelength?
Divide the wave speed by the frequency. For a sound wave at 100 hertz traveling at 343 meters per second, the wavelength is 343 divided by 100, or 3.43 meters. Enter the frequency, select frequency as the known value, and give the wave speed, and the calculator returns the wavelength.
How do you convert wavelength to frequency?
Divide the wave speed by the wavelength. A 3.43-meter sound wave in air, where speed is 343 meters per second, has a frequency of 343 divided by 3.43, or 100 hertz. Select wavelength as your known value, enter it with the wave speed, and the calculator computes the frequency.
What wave speed should I use?
Use the speed appropriate to your wave and medium. Light and radio waves travel at about 299,792,458 meters per second in a vacuum. Sound travels around 343 meters per second in air at room temperature, faster in water and solids. Using the correct speed is essential, since it links frequency and wavelength.
Why are frequency and wavelength inversely related?
Because their product equals the fixed wave speed, if one increases the other must decrease. A higher frequency means more cycles per second packed into the same speed, so each cycle is shorter, giving a shorter wavelength. This inverse relationship holds for all waves at a given speed in a given medium.
Does this work for light and radio waves?
Yes. The relationship applies to all waves, including electromagnetic ones like light, radio, and microwaves. Just use the speed of light, about 299,792,458 meters per second in a vacuum, as the wave speed. This is how radio frequencies are converted to wavelengths for antenna design and how light frequencies relate to color.