Convert any frequency to wavelength, or wavelength to frequency. Includes λ/2 and λ/4 values for antenna design.
Frequency → Wavelength
Wavelength (λ)
Wavelength in cm
Wavelength in mm
Half wavelength (λ/2)
Quarter wavelength (λ/4)
Wavelength → Frequency
Frequency in Hz
Frequency in kHz
Frequency in MHz
Frequency in GHz
Frequently Asked Questions
What is wavelength in RF?
Wavelength (λ) is the physical distance one complete cycle of a radio wave travels in free space. It is calculated as the speed of light (approximately 299,792,458 m/s) divided by the frequency in Hz. Lower frequencies have longer wavelengths — for example, an AM radio signal at 1 MHz has a wavelength of about 300 meters — while higher frequencies have shorter wavelengths, such as a 5G mmWave signal at 28 GHz with a wavelength of just under 11 mm.
Why is λ/4 important for antennas?
A quarter-wavelength (λ/4) is the most fundamental resonant length for a monopole antenna. When an antenna element is exactly λ/4 long, it presents a nearly purely resistive impedance at its feed point (about 35–50 Ω over a ground plane), making it efficient and easy to match. Dipole antennas are λ/2 (two quarter-wave elements), and many other antenna types — including whips, patch elements, and Yagi directors — are derived from λ/4 or λ/2 as their starting dimension.
What is the wavelength of 5G frequencies?
5G operates in two main frequency ranges. Sub-6 GHz 5G (600 MHz to 6 GHz) has wavelengths ranging from about 500 mm down to 50 mm, similar to 4G LTE. 5G mmWave (24 GHz to 52 GHz) has wavelengths between approximately 5.8 mm and 12.5 mm — hence the name "millimeter wave." The very short mmWave wavelengths enable compact antenna arrays (massive MIMO) but result in high free space path loss and limited building penetration.