This wave speed calculator solves the universal wave equation v = fλ — enter any two of speed, frequency and wavelength to get the third.

Leave the field you want to solve for empty (or zero) — the calculator fills exactly one unknown.

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One Equation, Every Wave in Physics

Sound, light, water, seismic, strings — v = fλ governs them all because it merely says: each cycle advances one wavelength, f times per second. Our Wavelength Calculator focuses on electromagnetic and de Broglie cases. Part of our Physics Calculators collection.

Worked Example (Verified)

  • Sound at 256 Hz in air (defaults, v = 343): λ = 343/256 = 1.34 m — middle-C-ish wavelengths are furniture-sized, which is why bass wraps around rooms
  • The same 256 Hz in water (v ≈ 1,480): λ = 5.78 m — frequency unchanged, wavelength stretched by the faster medium
  • FM radio at 100 MHz: λ = 3.00 m (c ÷ f) — car antennas are quarter-wave stubs ≈ 0.75 m of this very arithmetic
  • Ultrasound imaging at 5 MHz in tissue (v ≈ 1,540): λ = 0.31 mm — resolution lives at the wavelength scale, hence megahertz probes

Medium Makes the Speed

  • Sound speeds up in warmer air (+0.6 m/s per °C) and far faster in liquids/solids.
  • Light slows in media (v = c/n) — the refraction mechanism our Snell’s Law Calculator exploits.
  • Water waves disperse (v depends on λ and depth), breaking the tidy rule — shallow-water v = √(gd).
  • On strings, v = √(T/μ): tension up, speed up — the physics inside tuning pegs.

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Frequently Asked Questions

How do you calculate wave speed?

v = f × λ: frequency (Hz) times wavelength (m). A 256 Hz tuning fork in air: 256 × 1.34 ≈ 343 m/s. Given any two of the three quantities, this calculator finds the third.

Does frequency change when a wave enters a new medium?

No — the source sets frequency, and wavefronts can’t pile up or vanish at the boundary. Speed changes (the medium’s property), so wavelength stretches or compresses to keep v = fλ true. Pitch survives the pool wall; wavelength doesn’t.

What is the speed of sound?

≈ 343 m/s in dry air at 20 °C, rising ~0.6 m/s per °C; ≈ 1,480 m/s in water and ~5,960 m/s in steel. Temperature, medium and (for gases) composition all enter — 343 is the classroom default this page opens with.

How is wavelength related to energy for light?

E = hc/λ: shorter wavelength, higher photon energy — ultraviolet out-punches infrared per photon. The Photon side of the story lives on the Wavelength Calculator linked above.

Why do bass sounds travel around corners better?

Diffraction scales with wavelength relative to obstacles: a 40 Hz wave (λ ≈ 8.6 m) bends around doorways and furniture that block a 4 kHz wave (λ ≈ 8.6 cm) outright — your neighbor’s subwoofer is a wavelength argument.

Is this wave speed calculator free?

Yes — free, instant, no sign-up.