Find wave velocity using simple physics inputs. Choose what to solve and switch units fast. Download CSV or PDF to share your results easily.
| Wave Type | Wavelength (λ) | Frequency (f) | Velocity (v = λ × f) |
|---|---|---|---|
| Sound (air, approx) | 0.343 m | 1.0 kHz | 343 m/s |
| Sound (short wavelength) | 0.0343 m | 10 kHz | 343 m/s |
| Water wave | 2.0 m | 0.50 Hz | 1.0 m/s |
| Microwave (vacuum, approx) | 0.12 m | 2.5 GHz | 3.0×108 m/s |
| Green light (vacuum, approx) | 532 nm | 563 THz | 3.0×108 m/s |
Core relationship: v = λ × f
Rearranged forms:
Wave velocity tells you how fast energy and information travel through a medium. In acoustics it affects echo timing and room measurements. In optics it helps relate color to frequency. In communications it supports bandwidth planning and timing calculations for signals moving through cables.
This calculator uses the standard wave equation v = λ × f. When frequency increases while velocity stays constant, wavelength decreases. When wavelength increases, frequency must drop for the same speed. The tool also rearranges it to λ = v ÷ f and f = v ÷ λ.
At about 20°C, sound in air travels near 343 m/s. A 1 kHz tone then has λ ≈ 0.343 m, while a 10 kHz tone has λ ≈ 0.0343 m. At 100 Hz, wavelength is about 3.43 m in air. These values are useful for microphone spacing, speaker placement, and acoustic panel sizing.
Electromagnetic waves in vacuum travel near 3.00×108 m/s. A 2.5 GHz microwave has λ ≈ 0.12 m. Green light around 532 nm corresponds to roughly 5.6×1014 Hz. In materials, the speed is lower due to refractive index.
Infrasound is below 20 Hz and can have wavelengths of many meters in air. Ultrasound is above 20 kHz, producing centimeter to millimeter wavelengths. These short wavelengths enable imaging resolution improvements and precise distance measurement using time-of-flight methods.
For surface water waves, speed can depend on wavelength and depth, so the “velocity” may vary across frequencies. Still, v = λ × f holds for a measured wave: if you observe λ and f, the calculated v matches the observed motion.
Small optical wavelengths are often in nm, while audio wavelengths are in meters. Frequencies span from Hz to THz. This calculator converts inputs to SI units before solving, then displays results in multiple units such as m/s, km/h, mph, and ft/s. That makes quick cross-checks much easier.
If your computed velocity is far from expected, recheck units first: GHz vs MHz, nm vs µm, and km/h vs m/s are common mistakes. For best comparisons, keep temperature and medium consistent because wave speed changes with material properties and conditions.
Q1. What is the correct formula for wave speed?
Wave speed is found using v = λ × f, where λ is wavelength and f is frequency. If you know any two quantities, you can solve for the third by rearranging the equation.
Q2. Can this calculator be used for both sound and light?
Yes. The relationship is the same for any wave. The difference is the medium: sound speed depends on air temperature and pressure, while light speed changes with the material’s refractive index.
Q3. Why do I get a different velocity than 343 m/s for sound?
Because real conditions vary. Temperature, humidity, and gas composition can change the speed of sound. Also verify that frequency is in Hz and wavelength is in meters after unit selection.
Q4. When should I use scientific notation?
Use it for very large or small values, such as THz frequencies or nanometer wavelengths. Scientific notation keeps results readable and reduces rounding confusion in extreme ranges.
Q5. What units does the calculator accept?
It accepts wavelength in meters, centimeters, millimeters, micrometers, nanometers, angstroms, feet, and inches. Frequency can be entered in Hz through THz. Velocity can be entered in m/s, km/s, km/h, ft/s, or mph.
Q6. Does the equation work for waves in water?
Yes for measured waves, but water waves can be dispersive, meaning speed may change with wavelength and depth. If you measure λ and f from the same wave, v = λ × f matches its observed speed.
Q7. How do I check if my answer is reasonable?
Compare your velocity with typical values for the medium. For air sound, expect hundreds of m/s. For light in vacuum, expect about 3×10^8 m/s. Large mismatches usually indicate a unit selection issue.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.