Frequency and Wavelength Calculator
Calculate wavelength from frequency using a selected propagation speed
The default wave speed is the speed of light in vacuum.
Wavelength
How we calculated it
About the Frequency and Wavelength Calculator
Frequency and wavelength describe repeating waves from two complementary perspectives: how many cycles pass per second and how long each cycle is in space. Wave speed links the two.
This relationship appears in sound, radio, light and other wave systems, but the relevant propagation speed depends on the medium.
How to Use the Frequency and Wavelength Calculator
- Enter the known frequency or wavelength.
- Enter or select the wave speed appropriate to the medium.
- Calculate the missing wavelength or frequency.
- Check metric prefixes carefully because hertz, kilohertz, megahertz and gigahertz differ by large powers of ten.
How the Calculation Works
Wave speed is v = fλ, where f is frequency and λ is wavelength. Rearranging gives λ=v/f and f=v/λ.
For electromagnetic waves in vacuum, v is approximately the speed of light. Sound and other waves require the appropriate medium-dependent speed instead.
Worked example
Frequency and Wavelength Calculator Worked Example
100 MHz radio wave in vacuum
Frequency = 100 MHz = 100,000,000 Hz. Using about 3.00×10⁸ m/s, wavelength = 3.00×10⁸ ÷ 1.00×10⁸ ≈ 3 m.
Result guide
Understanding Your Frequency and Wavelength Calculator Result
For a fixed wave speed, higher frequency means shorter wavelength. If the propagation speed changes in a medium, wavelength changes even when frequency remains fixed across the boundary.
Before you rely on the answer
Assumptions and Limitations
- Wave speed matches the medium and conditions.
- Frequency and wavelength refer to the same wave.
- Relativistic or dispersive effects are excluded unless the selected speed already reflects them.
Practical tip
Using This Result in Practice
Convert prefixes before checking the arithmetic manually. Confusing MHz with Hz changes the result by a factor of one million.
Related calculations
Useful Calculations to Continue With
If you only need to convert hertz, kilohertz, megahertz or gigahertz, use the Frequency Converter.
The same distance-per-time structure underlies wave speed; use the Speed Distance Time Calculator for ordinary travel relationships.
Common questions
Frequency and Wavelength Calculator FAQ
What is the formula relating frequency and wavelength?
v=fλ, where v is wave speed, f is frequency and λ is wavelength.
What happens to wavelength when frequency increases?
For a fixed wave speed, wavelength decreases in inverse proportion.
Is the speed of every wave equal to the speed of light?
No. Electromagnetic waves in vacuum travel at light speed; sound and other waves use different medium-dependent speeds.