The Physics of the Universe
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Wave Speed Calculator

Calculate wave speed from frequency and wavelength using v = f × λ — or solve for frequency or wavelength. Works for sound, light and any wave, without needing distance or time.

 

Formula

$$ v = f\,\lambda \qquad f = \frac{v}{\lambda} \qquad \lambda = \frac{v}{f} $$

Worked example

A 170 Hz sound with a 2 m wavelength travels at \( v = f\lambda = 170 \times 2 = 340\ \text{m/s} \) — the speed of sound in air. For light, using v = c = 3×10⁸ m/s lets you convert between frequency and wavelength.

How it works

Every wave obeys v = f λ: its speed equals its frequency (cycles per second, Hz) times its wavelength (the length of one cycle, m). This lets you find the speed without measuring distance and time directly.

The relationship applies to all waves — sound (~340 m/s in air), water waves and electromagnetic waves (light, at c = 3×10⁸ m/s). For a fixed wave speed, higher frequency means shorter wavelength, and vice versa.

Frequently asked questions

How do you calculate wave speed without time?

Use v = f λ — multiply the frequency (Hz) by the wavelength (m). You don't need distance or time; frequency and wavelength alone give the speed.

What is the formula linking speed, frequency and wavelength?

v = f λ. Rearranged, frequency f = v/λ and wavelength λ = v/f. Set 'Solve for' to whichever quantity you need.

What is the wave speed of light and sound?

Light travels at c = 3×10⁸ m/s in a vacuum. Sound travels far slower — about 340 m/s in air at room temperature and faster in water and solids.

If frequency doubles, what happens to wavelength?

At constant wave speed, doubling the frequency halves the wavelength, because their product v = fλ must stay the same.

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