RF Frequency to Wavelength Calculator
Convert radio frequency to wavelength for antenna design and RF engineering.
Supports Hz through GHz with results in meters, centimeters, and millimeters.
Wavelength
Frequency and wavelength are inversely related through the universal wave equation, which applies to all electromagnetic radiation — from radio waves to gamma rays.
The Core Formula:
λ = c / f
Where:
- λ (lambda) = Wavelength in meters (m)
- c = Speed of light in vacuum = 299,792,458 m/s ≈ 3 × 10⁸ m/s
- f = Frequency in Hertz (Hz)
Rearranged:
f = c / λ
Energy of a photon (Planck’s equation):
E = h × f = h × c / λ
Where h (Planck’s constant) = 6.626 × 10⁻³⁴ J·s
Worked Example — FM Radio:
- Station frequency: 98.1 MHz = 98,100,000 Hz
- Wavelength: λ = 3 × 10⁸ / 98,100,000 = 3.058 meters
- This is why FM antennas are roughly 75 cm long (quarter-wave dipole = λ/4)
Electromagnetic Spectrum Reference:
| Band | Frequency | Wavelength |
|---|---|---|
| AM Radio | 535–1,705 kHz | 176–561 m |
| FM Radio | 87.5–108 MHz | 2.8–3.4 m |
| WiFi 2.4 GHz | 2.4 GHz | 12.5 cm |
| WiFi 5 GHz | 5 GHz | 6 cm |
| Visible Light | 400–700 THz | 430–750 nm |
| X-Rays | 30 PHz–30 EHz | 0.01–10 nm |
Practical Use: Antenna designers use this formula to cut wire lengths to exact fractions of the target wavelength. A half-wave dipole for 2.4 GHz WiFi is exactly 6.24 cm long.