Wave Frequency Calculator
Solve for wave speed, frequency, wavelength, period, or photon energy. Supports sound, light, radio, and all wave types using v = fλ, T = 1/f, and E = hf. No signup, runs entirely in your browser.
Wave Physics Tips
Audible range
Human hearing covers 20 Hz to 20,000 Hz. At 343 m/s, that corresponds to wavelengths from ~17 m (20 Hz) down to ~1.7 cm (20 kHz).
Visible light range
Visible light spans ~380–700 nm wavelength. Use c = 3×10⁸ m/s and convert nm to m (1 nm = 1×10⁻⁹ m) before entering values.
Radio waves
FM radio broadcasts at 87.5–108 MHz. At c, that gives wavelengths of roughly 2.8–3.4 m — consistent with the antenna lengths used on vehicles.
Period vs frequency
If you know the period from an oscilloscope trace, enter it to solve for frequency. A 20 ms period equals 50 Hz — the standard AC frequency in Europe.
Frequently Asked Questions
What is the wave equation v = fλ?
The wave equation states that the speed of a wave equals its frequency multiplied by its wavelength. For example, sound traveling at 343 m/s with a wavelength of 0.343 m has a frequency of 1000 Hz (1 kHz).
What is the relationship between period and frequency?
Period (T) and frequency (f) are reciprocals: T = 1/f and f = 1/T. A wave with a frequency of 100 Hz completes one full cycle every 0.01 seconds (10 ms period).
What is photon energy and how is it calculated?
Photon energy is calculated using E = hf, where h is Planck's constant (6.626 × 10⁻³⁴ J·s). A visible light photon at 600 nm has a frequency of ~5 × 10¹⁴ Hz and energy of ~3.3 × 10⁻¹⁹ J.
What wave speed should I use for sound?
The speed of sound in dry air at 20°C is approximately 343 m/s. It varies with temperature: roughly 331 + 0.6 × T(°C) m/s. In water it is ~1480 m/s; in steel ~5960 m/s.
What speed should I use for light?
The speed of light in a vacuum is exactly 299,792,458 m/s (≈ 3 × 10⁸ m/s). In glass or water, light travels slower by a factor called the refractive index.
Is my data stored?
No. All calculations run locally in your browser. No data is sent to any server.