Wave Speed Calculator
Find a wave’s speed from its frequency and wavelength, plus its period, using v = f·λ.
How it works
v = f·λ · period T = 1/f
A travelling wave’s speed equals its frequency times its wavelength — how many cycles pass each second multiplied by the length of one cycle. In a given medium the speed is fixed, so raising the frequency shortens the wavelength and vice versa. This one relation covers sound, water waves, waves on a string and electromagnetic waves alike; only the value of the speed changes with the medium.
Worked example
A 500 Hz sound wave with a 0.68 m wavelength travels at v = 500 × 0.68 = 340 m/s — the speed of sound in room-temperature air. Its period is 1/500 = 0.002 s.
Sources: Wave — Wikipedia
Frequently asked questions
What is the wave speed of light?
In a vacuum, electromagnetic waves travel at c ≈ 299,792,458 m/s. For light you can enter c as the speed and solve for wavelength or frequency instead, since v = f·λ still holds.
Does frequency or wavelength set the speed?
Neither — the medium does. Sound in air travels near 340 m/s whatever its frequency; changing the frequency changes the wavelength to keep the product constant. Speed only changes when the wave enters a different medium.
What is the period?
The period is the time for one full cycle, the reciprocal of frequency. A 500 Hz wave repeats every 1/500 = 0.002 seconds.
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