Frequency to Wavelength Converter
Convert frequency to wavelength and wavelength to frequency for electromagnetic waves.
Frequency → Wavelength
Wavelength → Frequency
About this calculator
Convert frequency to wavelength and wavelength to frequency for electromagnetic waves in a vacuum or in air. Choose Hz, kHz, MHz or GHz.
Used in radio, Wi-Fi, antenna design and optics.
How to use it
- Enter the frequency and choose the unit.
- Read the wavelength.
- Or enter a wavelength to get the frequency.
The wave equation
λ = c ÷ f, where c = 299,792,458 m/s (about 3 × 10⁸ m/s). A higher frequency means a shorter wavelength. In other media, divide c by the refractive index. A quarter-wave antenna is λ ÷ 4 long.
Worked example
Common bands
| FM radio, 100 MHz | 3.0 m |
| Wi-Fi, 2.4 GHz | 12.5 cm |
| Wi-Fi, 5 GHz | 6.0 cm |
| Visible green light, 540 THz | 555 nm |
Tips and common mistakes
- Use 3 × 10⁸ m/s for quick estimates.
- Keep units consistent: MHz with metres makes λ = 300 ÷ f(MHz).
- In cables, waves travel slower, at about 66% of c in coax.
- Antenna length scales with wavelength.
- Higher frequencies have less range through walls.
Frequently asked questions
What is the formula?
Wavelength = speed of light ÷ frequency.
What is the wavelength of 100 MHz?
3 metres.
What is the wavelength of Wi-Fi 2.4 GHz?
About 12.5 cm.
Does a higher frequency mean a longer wavelength?
No, shorter.
What is c?
299,792,458 m/s.
Is it free?
Yes.