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Wave Speed, Frequency and Wavelength Calculator

Use v = f × λ to find wave speed, frequency or wavelength, for light, radio, sound or any wave.

Used with “Enter a speed”.

Result

Enter your values and select Calculate to see the result.

Runs in your browser — nothing you enter is sent to a server.

How the Wave Speed, Frequency and Wavelength Calculator works

Every wave obeys v = f × λ: speed equals frequency times wavelength. Choose what to find, pick the wave speed — light and radio in a vacuum, sound in air, or your own — and enter the other value with its unit. The result also gives the period, the time for one cycle.

Formula

v = f × λ, T = 1 ÷ f

The speed of light is exactly 299,792,458 m/s; sound in air at 20 °C travels at about 343 m/s.

Examples

An FM radio station at 100 MHz

λ = 299,792,458 ÷ 100,000,000 ≈ 3.0 m, with a period of 10 ns.

The note A at 440 Hz

In air, λ = 343 ÷ 440 ≈ 0.78 m.

Frequently asked questions

Does light slow down in glass?

Yes — in glass it travels about a third slower, so its wavelength shortens while the frequency stays the same.

What frequency is green light?

Light of 500 nm has a frequency of about 6.0 × 10¹⁴ Hz.

Why does sound speed change?

It depends on the medium and temperature: faster in warm air, much faster in water and steel.

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