Wave Speed Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/6/2026
A wave's propagation speed is calculated with v = λ × f (wavelength multiplied by frequency). For a wavelength of 2 m and a frequency of 5 Hz, the speed is 10 m/s.
Explanation
This fundamental relationship links three quantities that describe a periodic wave (sound, light, or a wave on the surface of water): its wavelength (λ, the distance between two successive crests, in meters), its frequency (f, the number of oscillations per second, in hertz), and its propagation speed (v, in meters per second). The higher the frequency for the same propagation speed, the shorter the wavelength, and vice versa — a principle that explains, for example, why high-pitched sounds (higher frequency) have a shorter wavelength than low-pitched sounds, at the same speed of sound. This formula applies to any type of periodic wave, but the propagation speed itself depends on the medium: sound travels at about 340 m/s in air at room temperature, but much faster in water or in a solid; light travels at about 3 × 10⁸ m/s in a vacuum, but more slowly in a material medium.
Example: a sound wave at 340 Hz
Inputs
Wavelength: 0.5 m. Frequency: 340 Hz.
Calculation
Speed = 0.5 × 340 = 170 m/s.
Result
This wave propagates at 170 m/s in the medium considered.
Frequently asked questions
Does this formula work for light the same way as for sound?
Yes, the relationship v = λ × f applies to any periodic wave phenomenon, whether a sound, light, or mechanical wave. Only the value of the propagation speed changes depending on the type of wave and the medium it travels through.
Why does the speed of sound vary depending on the medium?
A sound wave's propagation speed depends on the physical properties of the medium (density, elasticity, temperature). In air at 20°C, it's about 340 m/s; it's noticeably faster in water (about 1,480 m/s) and in most solids, where molecules are closer together and transmit the vibration more efficiently.
If I know the speed and the frequency, can I find the wavelength?
Yes, the same relationship rearranges to λ = v ÷ f. This calculator is set up to find the speed from the wavelength and frequency; for the reverse use, simply apply that division manually.