About the Wavelength Calculator
What is the Wavelength Calculator?
Wavelength is the distance a wave travels in one cycle. This wavelength calculator divides the wave's speed by its frequency for radio and light, sound in air or water, or any custom speed.
For radio work, it also gives the length of a half-wave dipole antenna and a quarter wavelength.
How to use the Wavelength Calculator
- Frequency (sample: 2.4)
- Frequency Unit (sample: GHz)
- Wave (sample: Radio / light in vacuum or air (299,792,458 m/s))
- Custom Wave Speed (m/s) (sample: 1,000)
- Press Calculate Wavelength (results also refresh as you type). The result card shows the Wavelength, along with Readable, Half-wave dipole length (radio), Quarter wavelength and Wave speed used.
Formula used
λ = v ÷ f
- v = light 299,792,458 m/s; sound in air at 20 °C 343 m/s; sound in water 1,481 m/s
- Dipole length = λ ÷ 2 × 0.95 (end-effect correction)
Light travels slightly slower in cables and glass, so physical lengths there are shorter.
Worked example
These are the sample values already filled in the calculator above, and the result it returns for them:
| Input | Sample value |
|---|---|
| Frequency | 2.4 |
| Frequency Unit | GHz |
| Wave | Radio / light in vacuum or air (299,792,458 m/s) |
| Custom Wave Speed (m/s) | 1,000 |
| Result | Value |
|---|---|
| Wavelength | 0.124914 m |
| Readable | 12.4914 cm |
| Half-wave dipole length (radio) | 0.0593 m |
| Quarter wavelength | 0.0312 m |
| Wave speed used | 29,97,92,458 m/s |
Tips for using the Wavelength Calculator
- Wi-Fi at 2.4 GHz has a wavelength of about 12.5 cm; at 5 GHz about 6 cm.
- FM radio (88–108 MHz) wavelengths are about 3 m.