Frequency to Wavelength Converter | f = c/λ
Convert between frequency and wavelength using f=c/λ. Supports units from Hz to THz and nm to km. Useful for RF, microwave, and optical engineering.
How to Use
- Select conversion direction: 'Frequency → Wavelength' or 'Wavelength → Frequency'.
- Enter the value and select the appropriate unit (Hz to THz for frequency, nm to km for wavelength).
- Click 'Convert' to calculate the result.
- The tool uses c = 299,792,458 m/s (speed of light in vacuum).
- For media other than vacuum (e.g. fiber optic glass with n=1.5), wavelength in medium = wavelength in vacuum / n.
- The photon energy in eV is also shown, which is useful for optical and RF applications.
About Frequency and Wavelength
The f = c/λ Relationship
For electromagnetic waves in vacuum, frequency and wavelength are related by f = c/λ, where c = 299,792,458 m/s ≈ 3×10⁸ m/s. Higher frequency means shorter wavelength; lower frequency means longer wavelength. This relationship spans the entire electromagnetic spectrum from radio waves (km wavelength, kHz frequency) to gamma rays (pm wavelength, EHz frequency). The frequency determines the wave's energy; the wavelength determines its penetration and diffraction behavior.
The Electromagnetic Spectrum
Frequency bands: Radio (3 Hz–300 MHz, λ=1mm–100,000km), Microwave (300 MHz–300 GHz, λ=1mm–1m), Infrared (300 GHz–430 THz, λ=700nm–1mm), Visible (430–790 THz, λ=380–700nm): red=700nm, orange=620nm, yellow=580nm, green=530nm, blue=470nm, violet=400nm. UV (790 THz–30 PHz), X-ray (30 PHz–30 EHz), Gamma (>30 EHz). Each band interacts differently with matter and has distinct applications.
Common Frequency Bands in Electronics
Key RF bands: AM broadcast = 535–1705 kHz (λ≈175–560m), FM broadcast = 87.5–108 MHz (λ≈2.8–3.4m), WiFi 2.4 GHz (λ=12.5cm), WiFi 5 GHz (λ=6cm), WiFi 6E/6 GHz (λ=5cm), 4G LTE 700 MHz (λ=43cm) to 2.6 GHz (λ=11.5cm), 5G mmWave 24–100 GHz (λ=3–12.5mm), GPS L1 = 1575.42 MHz (λ=19cm). Antenna size is related to wavelength — half-wave dipoles are λ/2 long.
Wavelength in Different Media
In vacuum, speed of light c = 3×10⁸ m/s. In other media, the wave slows by the refractive index n: v = c/n. Wavelength in medium = λ_vacuum / n. For glass fiber (n≈1.5): 1550nm optical wavelength in vacuum = 1033nm in glass. In RF circuit traces (εr≈4), the effective wavelength is about half of the free-space value. This is why PCB antenna designs are shorter than free-space quarter-wave calculations would suggest.
Key Features
- Bidirectional conversion: frequency ↔ wavelength
- Supports Hz to THz and nm to km unit ranges
- Shows angular frequency ω and photon energy in eV
- Identifies the electromagnetic spectrum band
Common Applications
- Antenna length calculation for radio and microwave systems
- Optical fiber and laser wavelength conversion
- RF cavity and waveguide resonator design
- Spectroscopy and photonic device design
- EMC wavelength estimation for shielding and filtering