Wave Speed
Solve for wave speed, frequency, or wavelength using v = fλ. Great for school physics and wave-motion practice with step-by-step working.
Key formula
v = f lambda
How do you calculate wave speed?
Wave speed is v = f × λ. Multiply frequency by wavelength. Rearrange to f = v/λ or λ = v/f. Keep f in hertz and λ in metres for v in metres per second.
About this tool
Wave speed links how often waves pass a point to how long each wave is. This page keeps v = fλ visible so you can solve for speed, frequency, or wavelength without mixing Hz and metres.
How to use this calculator
- Choose the variable you want to solve for and confirm which values are already known.
- Enter inputs in consistent units before calculating so the formula is applied correctly.
- Check whether the result is physically reasonable by comparing it with the size of the inputs.
- Use the step-by-step breakdown to see how the equation was rearranged and evaluated.
Worked examples
Example 1: find wave speed
f = 50 Hz, λ = 2.0 m. v = f λ = (50)(2.0) = 100 m/s.
Example 2: find wavelength
v = 340 m/s (approx. air), f = 170 Hz. λ = v/f = 340/170 = 2.0 m.
Example 3: find frequency
v = 3.0 × 10⁸ m/s, λ = 0.50 m. f = v/λ = 6.0 × 10⁸ Hz.
Frequently asked questions
What is the wave speed formula?
v = f λ, where f is frequency in hertz and λ is wavelength in metres. Rearrangements are f = v/λ and λ = v/f.
Does wave speed depend on frequency?
In many intro problems the medium fixes v, so changing f changes λ to keep v = fλ. In dispersive media, speed can depend on frequency — use the value the problem gives.
What units should I use?
Use Hz for frequency and metres for wavelength to get m/s. Convert kHz → Hz (×1000) and cm → m (÷100) before substituting.
Is wave speed the same as particle speed?
No. Wave speed is how fast the disturbance travels. Particles of the medium oscillate locally; they do not travel with the wave at speed v.
How does this relate to light or sound?
The same v = fλ applies. Sound in air is often near 340 m/s; light in vacuum is about 3.0 × 10⁸ m/s. Use the speed the problem states.