Quick answer
Wavelength λ = v ÷ f. Sound at 343 m/s with a frequency of 440 Hz has a wavelength of 0.7795 m and a period of 2.27 ms.
Enter the wave speed and frequency. The calculator returns the wavelength in metres and the period.
Related tools: Photon Energy Calculator: Photon energy from wavelength or frequency. Wavelength to Frequency Calculator: Frequency of an electromagnetic wave from its wavelength in vacuum. Dew Point Calculator: Dew point from temperature and relative humidity.
How to use the Wavelength Calculator
- Enter wave speed (m/s) (above 0). It starts at 299792458.
- Enter frequency (Hz) (above 0).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Wave speed | A number, in m/s | > 0, starts at 299792458 |
| Frequency | A number, in Hz | > 0 |
Formula and method
Formula
λ = v ÷ f
IEEE-754 double precision; shown to the decimals indicated.
Defaults to the speed of light in vacuum; use 343 m/s for sound in air.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Wave speed = 343; Frequency = 440.
| Result | Value |
|---|---|
| Wavelength | 7.795455e-1 m |
| Period | 2.2727e-3 s |
Example 2
Inputs: Wave speed = 299792458; Frequency = 100000000.0.
| Result | Value |
|---|---|
| Wavelength | 2.997925e+0 m |
| Period | 1.0000e-8 s |
Example 3
Inputs: Wave speed = 1500; Frequency = 2500.
| Result | Value |
|---|---|
| Wavelength | 6.000000e-1 m |
| Period | 4.0000e-4 s |
The first line is the headline result (wavelength). Below it the wavelength Calculator lists period, which describe the same case from other angles. IEEE-754 double precision; shown to the decimals indicated.
Different waves
For sound in air use about 343 m/s; for light and radio waves 299,792,458 m/s. FM radio at 100 MHz has λ = 3 m. Doubling the frequency halves the wavelength.
Period
The period T = 1 ÷ f = 2.27 ms here. Wavelength, frequency and speed describe waves on strings, in water and in air. The result is in metres.
How the result changes with wave speed
Holding every other input at the first worked example, this table changes only wave speed. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Wave speed | Wavelength | Period |
|---|---|---|
| 171.5 | 3.897727e-1 m | 2.2727e-3 s |
| 343 | 7.795455e-1 m | 2.2727e-3 s |
| 686 | 1.559091e+0 m | 2.2727e-3 s |
| 1372 | 3.118182e+0 m | 2.2727e-3 s |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Frequency: entering "0" shows "Frequency must be greater than 0." beside that field and no result.
- Wave speed: entering "0" shows "Wave speed must be greater than 0." beside that field and no result.
Choosing between the Wavelength Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Photon Energy Calculator](/science/photon-energy-calculator/) | start from and wavelength or frequency | Photon energy |
| [Wavelength to Frequency Calculator](/converters/wavelength-to-frequency/) | wavelength | Frequency |
| [Dew Point Calculator](/science/dew-point/) | air temperature and relative humidity | Dew point |
| [Acceleration Calculator](/science/acceleration-calculator/) | initial velocity, final velocity and time | Acceleration |
| [Mole Calculator](/science/mole/) | start from and molar mass | Amount |
Background: gravity, rotation and optics
Gravity and rotation calculations use a few core relations: a circular orbit has speed v = √(GM ÷ r), torque equals moment of inertia times angular acceleration (τ = Iα), and a thin lens obeys 1/f = 1/dₒ + 1/dᵢ. The moment of inertia depends on both the shape and the axis of rotation.
Use SI units (metres, kilograms, seconds) and check the sign conventions of the formula before interpreting a negative result.
Assumptions and limitations
- Result in meters
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for frequency and wave speed to confirm this.
Frequently asked questions
What is the wavelength of 1 kHz sound?
At 343 m/s a 1 kHz sound has a wavelength of 0.343 m.
How are wavelength and frequency related?
Inversely: for a fixed wave speed, doubling the frequency halves the wavelength (λ = v ÷ f).
What is the speed of sound in water?
Sound travels at about 1,480 m/s in water, more than four times its speed in air.
What does the Wavelength Calculator calculate?
Wavelength from wave speed and frequency. It returns Wavelength and Period.
What formula does the Wavelength Calculator use?
λ = v ÷ f. Defaults to the speed of light in vacuum; use 343 m/s for sound in air.
What do I need to enter in the wavelength Calculator?
You enter Wave speed (m/s) and Frequency (Hz).
How is the result rounded or limited?
IEEE-754 double precision; shown to the decimals indicated. Result in meters.
What is an example of a wavelength result?
With wave speed 343 and frequency 440, the wavelength is 7.795455e-1 m.
Related calculators
- Photon Energy Calculator — Photon energy from wavelength or frequency.
- Wavelength to Frequency Calculator — Frequency of an electromagnetic wave from its wavelength in vacuum.
- Dew Point Calculator — Dew point from temperature and relative humidity.
- Acceleration Calculator — Average acceleration from change in velocity over time.
- Mole Calculator — Convert between mass, moles and number of particles.
- Density Calculator — Solve mass, density or volume.
Sources
- CODATA 2018 / SI exact constants: g₀ = 9.80665 m/s², c = 299,792,458 m/s, h = 6.62607015×10⁻³⁴ J·s, e = 1.602176634×10⁻¹⁹ C, G = 6.67430×10⁻¹¹ m³/(kg·s²)
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.