How to Calculate Wavelength, Frequency, or Wave Speed
Choose which quantity to solve for, then enter the other two values. The calculator applies v = f × λ in your browser.
The Wave Equation and Unit Conversion
The wave equation relates wave speed v, frequency f, and wavelength λ (lambda):
v = f × λλ = v / f(solving for wavelength)f = v / λ(solving for frequency)
Inputs are converted to meters per second, hertz, and meters before calculation. Selected input units appear in the calculation steps; result statistics use these SI units.
- Wave speed: Meters/second (m/s), Kilometers/second (km/s), Kilometers/hour (km/h), Miles/hour (mph), Feet/second (ft/s), or Speed of light in vacuum (c).
- Frequency: Hertz (Hz), Kilohertz (kHz), Megahertz (MHz), Gigahertz (GHz), or Terahertz (THz).
- Wavelength: Kilometers (km), Meters (m), Centimeters (cm), Millimeters (mm), Micrometers (µm), or Nanometers (nm).
How to Use the Calculator
- Choose Solve for wavelength, Solve for frequency, or Solve for wave speed.
- Enter the other two values and select their units. For the fixed preset, choose Speed of light in vacuum (c); it uses
299792458 m/s. - Click Calculate to display the result and calculation steps.
- After a successful calculation, click Copy result or Download result (.txt).
- Click Reset to clear the values, restore the default units and wavelength mode, and hide the result or error state.
Input Validation and Calculation Limits
Enter numbers that match the accepted numeric format, are finite, and are strictly greater than zero. The calculator rejects empty, non-numeric, zero, and negative values, as well as values above 1e30. Some very small denominator values are checked against a 1e-30 threshold. Non-finite or underflowed calculated results can also be rejected.
Assumptions and Limitations
Apply the general wave equation to the values you supply. The calculator does not identify a wave type, infer propagation speed, or model medium effects, dispersion, or refraction beyond that speed. It does not calculate photon energy or other quantum quantities. The speed-of-light preset is intended for electromagnetic waves in a vacuum; provide the appropriate speed for other cases.
Calculation Privacy Behavior
The calculation script processes entered values in the browser and does not transmit those calculator values. This page also loads external analytics scripts, so broader data handling is not documented here.
Frequently Asked Questions
What is the wave equation formula?
The wave equation is v = f × λ, where v is wave speed, f is frequency, and λ (lambda) is wavelength. Rearranged, wavelength is λ = v / f and frequency is f = v / λ.
What units does this calculator support?
Frequency can be entered in hertz, kilohertz, megahertz, gigahertz, or terahertz. Wavelength can be entered in kilometers, meters, centimeters, millimeters, micrometers, or nanometers. Wave speed can be entered in meters per second, kilometers per second, kilometers per hour, miles per hour, feet per second, or selected as the speed of light in a vacuum.
Which two values do I need to enter?
Choose which quantity you want to solve for - wavelength, frequency, or wave speed - and enter the other two values needed to compute it.
Can frequency, wavelength, or speed be zero or negative in this calculator?
No. The calculator accepts only frequency, wavelength, and wave speed values that are strictly greater than zero.
Does this calculator know what kind of wave I am working with?
No. It applies v = f × λ to the speed you supply. It does not identify the wave type or infer its propagation speed. Select the built-in speed-of-light-in-vacuum preset for electromagnetic waves, or enter the relevant speed yourself.