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Wave Calculator

The wave calculator lets you instantly compute the wavelength, period, and wave number from a given frequency and wave propagation speed. It works for sound waves, radio waves, light, and any other wave type — just enter the appropriate wave speed for your medium.

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How to use the calculator?

Enter the wave frequency in hertz (Hz). Then enter the wave propagation speed in m/s — the default is the speed of sound in air (343 m/s). For radio waves or light, use 300 000 000 m/s. Click "Calculate" to instantly get the wavelength, period, and wave number.

Example calculation

Sound at 440 Hz (note A4) travels through air at 343 m/s. Wavelength: λ = 343 / 440 ≈ 0.7795 m. Period: T = 1 / 440 ≈ 0.002273 s (2.27 ms). Wave number: k = 2π / 0.7795 ≈ 8.059 rad/m.

Frequently asked questions

What is wavelength?

Wavelength is the distance between two consecutive points of a wave that are in the same phase, such as two crests or two troughs. It is measured in meters and denoted by the Greek letter λ (lambda).

How do you calculate wavelength?

Wavelength is calculated using the formula λ = v / f, where v is the wave speed (m/s) and f is the frequency (Hz). For example, for 440 Hz sound in air: λ = 343 / 440 ≈ 0.780 m.

What is wave period?

The wave period T is the time it takes to complete one full cycle of oscillation. It is calculated as T = 1 / f, where f is the frequency. For a 440 Hz wave, the period is approximately 2.27 ms.

The wave number k describes how many radians of phase occur per unit length. It is calculated as k = 2π / λ and expressed in rad/m. It is inversely proportional to the wavelength.

The speed of sound in air at 20°C is approximately 343 m/s. It depends on temperature, humidity, and atmospheric pressure. In water, the speed of sound is about 1480 m/s.

Electromagnetic waves (light, radio waves, microwaves) travel through vacuum at the speed of light c ≈ 299,792,458 m/s ≈ 3 × 10⁸ m/s. In the calculator you can enter 300000000.

For radio waves, use the speed of light (≈ 3 × 10⁸ m/s). For example, an FM station broadcasting at 100 MHz: λ = 300,000,000 / 100,000,000 = 3 m. This is why FM antennas are about 1.5 m long (half-wave).

Humans can hear sounds in the range of approximately 20 Hz to 20,000 Hz (20 kHz). Sounds below 20 Hz are infrasound, above 20 kHz are ultrasound. This corresponds to wavelengths from 17 mm to 17 m in air.

Yes, the calculator is universal. Just enter the appropriate wave speed: for electromagnetic waves in vacuum use 300,000,000 m/s, for sound in air use 343 m/s, for sound in water use 1480 m/s.

Frequency and wavelength are inversely proportional at a constant wave speed: the higher the frequency, the shorter the wavelength. The relationship is described by λ = v / f. Doubling the frequency halves the wavelength.

Results are indicative and calculated based on the provided inputs. Actual values may vary depending on the medium, temperature, and other physical factors.

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