PhysicsCalcs
Waves & Sound

Wavelength to Frequency Calculator

Convert wavelength to frequency using f = v/λ for visible light, RF, sound, and custom wave speeds.

Interactive calculator

Wave Frequency & Wavelength Calculator

Convert frequency to wavelength, wavelength to frequency, wave speed, and period using v = fλ.

Wave speed preset
λf, v

Quick Guide

  • Enter wavelength (m, cm, nm, pm, etc.).
  • Select wave speed preset or custom speed.
  • Try example presets (550 nm, 700 nm).
  • Review frequency, period, and visible color if applicable.

Table of Contents

Key Takeaways

  • Wavelength and frequency are related by v = fλ.
  • Frequency f = v / λ.
  • Shorter wavelength means higher frequency when wave speed is constant.
  • Visible light wavelengths are usually measured in nanometers (nm).
  • Sound frequency depends on wavelength and speed of sound in the medium.

What Is a Wavelength to Frequency Calculator?

It converts wavelength into frequency using wave speed. Useful for optics, RF, sound, and wave-motion learning.

For the reverse conversion, use the Frequency to Wavelength Calculator.

Wavelength to Frequency Formula

f=v/λf = v / λ

Optics and RF

Visible light uses nanometer wavelengths. 550 nm green light has frequency about 545 THz. 700 nm red light is about 430 THz. RF wavelengths are often meters or centimeters — a 3 m radio wave corresponds to roughly 100 MHz.

Examples

550 nm visible light

f ≈ 545 THz.

700 nm red light

f ≈ 428 THz.

3 m radio wave

f ≈ 99.93 MHz.

0.343 m sound in air

f = 343 / 0.343 = 1 kHz.

Common Wavelength-Frequency Values

WaveWavelengthFrequency
Green light≈ 550 nm≈ 545 THz
Red light≈ 700 nm≈ 430 THz
FM radio≈ 3 m≈ 100 MHz
Sound in air0.343 m1 kHz

Limitations

Ideal wave equations only. Optical wavelength in a medium differs from vacuum. Sound speed depends on temperature. Antenna design needs more than free-space wavelength.

FAQ

What is the formula for frequency from wavelength?›

f = v / λ, where v is wave speed in m/s and λ is wavelength in meters.

What is the frequency of 550 nm light?›

f = 299,792,458 / (550×10⁻⁹) ≈ 5.45×10¹⁴ Hz ≈ 545 THz.

What is the frequency of 700 nm red light?›

f ≈ 428 THz in vacuum.

What is the frequency of a 3 m radio wave?›

f = 299,792,458 / 3 ≈ 99.93 MHz.

What frequency is 0.343 m sound in air?›

f = 343 / 0.343 = 1000 Hz = 1 kHz.

Does wavelength change in different media?›

Yes. When wave speed changes in a medium, wavelength changes. Frequency typically stays constant across a boundary.

Is wavelength the same as period?›

No. Wavelength is distance per cycle; period is time per cycle. T = 1/f.

Sources

  1. NIST: speed of light (CODATA)
  2. OpenStax College Physics: Electromagnetic Waves
Manish Kumar

Author & technical reviewer

Manish Kumar

PhysicsCalcs tools are reviewed with an educational focus: clear formulas, transparent assumptions, and practical context for students and science learners.

Learn more about Manish