Frequency to Wavelength Calculator
Convert frequency into wavelength using the correct wave speed. Choose light, sound in air, sound in water, or enter a custom propagation speed.
Enter Frequency
The wavelength changes with both frequency and the speed of the wave through its medium.
Calculated Wavelength
Results update after you calculate, with the same wavelength shown in practical metric and imperial units.
How to Use the Frequency to Wavelength Calculator
- Enter the wave frequency.
- Select Hz, kHz, MHz, GHz, or THz.
- Choose the wave speed for light/radio, sound in air, sound in water, or select a custom speed.
- Click Calculate Wavelength to see the wavelength in multiple units and the calculation steps.
For sound, real-world wave speed changes with temperature, pressure, salinity, and other conditions. Use Custom Speed when you have a more precise propagation speed for your situation.
Frequency to Wavelength Formula
Wavelength is the distance a wave travels during one complete cycle. It depends on the wave frequency and the propagation speed through the selected medium.
- λ = wavelength in meters
- v = wave speed in meters per second (m/s)
- f = frequency in hertz (Hz)
At a fixed wave speed, frequency and wavelength are inversely related. Higher frequency means a shorter wavelength, while lower frequency means a longer wavelength.
Frequency and Wavelength Examples
These examples use common approximate propagation speeds. Your result can change if the medium or actual wave speed changes.
| Example | Frequency | Wave Speed | Approx. Wavelength |
|---|---|---|---|
| FM radio | 100 MHz | 299,792,458 m/s | 3.00 m |
| 2.4 GHz radio signal | 2.4 GHz | 299,792,458 m/s | 12.49 cm |
| Sound in air | 1 kHz | 343 m/s | 34.3 cm |
| Sound in water | 1 kHz | 1,480 m/s | 1.48 m |
Why Wave Speed Matters
The same frequency can have a different wavelength in different media because wavelength depends on propagation speed. Electromagnetic waves in vacuum travel at about 299,792,458 m/s, while sound travels much more slowly through air or water.
That is why a frequency-only conversion is incomplete unless the wave speed is known or assumed. This calculator lets you choose the medium or enter a custom speed so the result matches the type of wave you are working with.
Frequency to Wavelength Calculator FAQs
How do I calculate wavelength from frequency?
Divide the wave speed by the frequency. In SI units, use wave speed in meters per second and frequency in hertz to get wavelength in meters.
What is the wavelength of 100 MHz?
Using the speed of light in vacuum, 100 MHz corresponds to a wavelength of about 2.998 meters.
What is the wavelength of 2.4 GHz?
At the speed of light in vacuum, 2.4 GHz has a wavelength of about 0.1249 meters, or 12.49 centimeters.
Does wavelength change in different media?
Yes. When propagation speed changes while frequency remains the same, the wavelength changes. This is why selecting the correct wave speed matters.
Can I enter a custom wave speed?
Yes. Choose Custom Speed and enter any positive propagation speed in meters per second.
What frequency units does this calculator support?
The calculator supports hertz (Hz), kilohertz (kHz), megahertz (MHz), gigahertz (GHz), and terahertz (THz).