Calculators
Wavelength & Frequency Calculator
Solve wavelength, frequency, or wave speed with v = fλ.
Wavelength & Frequency Calculator tool
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About This Tool
Wavelength, frequency, and propagation speed are connected by the wave equation v = fλ. Frequency f tells how many cycles pass per second, wavelength λ is the distance between equivalent points on successive cycles, and v is the speed at which the wave pattern travels through its medium. This calculator solves any one of the three values and converts common units locally in your browser.
How To Use It
- Choose whether to solve for wavelength, frequency, or wave speed.
- Enter the two known positive values and choose their units.
- For sound or other medium-dependent waves, enter the wave speed that matches the actual medium and conditions rather than assuming one universal value.
- Choose a result unit and use the displayed equation to check how the result was obtained.
Examples
Simple sound-wave example
At a wave speed of 340 m/s and frequency of 170 Hz, λ = 340/170 = 2 m.
Find frequency
A 2 m wavelength traveling at 340 m/s has frequency f = 340/2 = 170 Hz.
Visible-scale wavelength
Using approximately 300,000 km/s for an electromagnetic-wave speed, a 500 nm wavelength corresponds to about 6 × 10^14 Hz.
Find wave speed
A 100 Hz wave with a 3.4 m wavelength travels at v = 100 × 3.4 = 340 m/s.
Useful Notes
Wave equation
The basic relationship is v = fλ. Rearranging gives λ = v/f and f = v/λ. Units must be consistent, so the calculator converts inputs to SI units before solving.
Frequency and wavelength
For a fixed wave speed, frequency and wavelength are inversely related: increasing frequency shortens wavelength, while decreasing frequency lengthens it.
Wave speed depends on the situation
The equation does not say that every wave travels at the same speed. Mechanical waves depend on their medium and conditions. Electromagnetic propagation also depends on the medium; use a speed appropriate to the problem.
Units and scale
Frequency is measured in hertz (cycles per second). Wavelength may range from metres to nanometres or beyond, so this tool supports metric prefixes from metres through nanometres and frequency units from hertz through terahertz.
Model limitations
This calculator applies the scalar wave relation to a single frequency and wavelength. It does not model dispersion, refraction, standing-wave boundary conditions, Doppler shift, attenuation, or changing wave speed across different media.
FAQ
What is the formula for wavelength?
Wavelength is λ = v/f: divide wave speed by frequency using consistent units.
Are frequency and wavelength always inversely proportional?
They are inversely related when wave speed is fixed. If propagation speed changes, the relationship must account for that new speed.
What does Hz mean?
One hertz means one cycle per second. kHz, MHz, GHz, and THz represent thousands, millions, billions, and trillions of cycles per second.
Can I use this for sound and light?
Yes for the basic v = fλ relationship, provided you enter an appropriate propagation speed and recognize that real media can introduce effects such as dispersion or refraction that this simple model does not calculate.