Frequency ↔ Wavelength Calculator
Enter a frequency or wavelength to instantly convert between the two. Includes ham band identification, licence class, and half-wave dipole lengths.
How the Formula Works
The relationship between frequency and wavelength is governed by one of the simplest equations in physics: λ = c / f. Here, λ (lambda) is the wavelength in meters, c is the speed of light (299,792,458 m/s), and f is frequency in hertz.
For example, the popular 2-meter calling frequency of 146.52 MHz converts to 146,520,000 Hz. Dividing the speed of light by this gives 299,792,458 / 146,520,000 ≈ 2.046 meters, which is why it's called the "2-meter band."
The formula works in reverse too: if you know the wavelength, just rearrange to f = c / λ. A 70-centimeter wavelength (0.7 m) gives 299,792,458 / 0.7 ≈ 428.3 MHz, placing it squarely in the 70cm UHF band.
Why Hams Need This
Antenna dimensions are directly tied to wavelength. The most common wire antenna, the half-wave dipole, needs to be cut to exactly half the operating wavelength. Get it wrong and your antenna won't resonate properly, leading to high SWR and wasted power.
Band planning is another reason. When you hear "the 20-meter band," that refers to the wavelength range around 14 MHz. Understanding the frequency-wavelength relationship helps you quickly identify where you are in the spectrum and what propagation characteristics to expect.
New to ham radio? Check out our best handheld radios for beginners to find a radio that covers the most popular VHF/UHF bands.
Common Ham Band Wavelengths
Here are the 16 US amateur radio band allocations with their frequency ranges and wavelength designations.
| Band | Frequency (MHz) | Category | Licence |
|---|---|---|---|
| 160m | 1.8–2 | HF | General |
| 80m | 3.5–4 | HF | General |
| 60m | 5.332–5.405 | HF | General |
| 40m | 7–7.3 | HF | General |
| 30m | 10.1–10.15 | HF | General |
| 20m | 14–14.35 | HF | General |
| 17m | 18.068–18.168 | HF | General |
| 15m | 21–21.45 | HF | General |
| 12m | 24.89–24.99 | HF | General |
| 10m | 28–29.7 | HF | Technician |
| 6m | 50–54 | VHF | Technician |
| 2m | 144–148 | VHF | Technician |
| 1.25m | 219–225 | VHF | Technician |
| 70cm | 420–450 | UHF | Technician |
| 33cm | 902–928 | UHF | Technician |
| 23cm | 1240–1300 | UHF | Technician |
Frequently Asked Questions
What is the formula for converting frequency to wavelength?
The formula is λ = c / f, where λ is wavelength in meters, c is the speed of light (299,792,458 m/s), and f is frequency in hertz. For example, 146.52 MHz = 146,520,000 Hz, so λ = 299,792,458 / 146,520,000 ≈ 2.046 meters.
Why do ham radio operators need to know frequency and wavelength?
Wavelength directly determines antenna dimensions. A half-wave dipole, the most common wire antenna, must be cut to half the operating wavelength. Knowing the conversion also helps operators identify which band a frequency falls in, choose the right equipment, and plan antenna installations.
What is the difference between HF, VHF, and UHF ham radio bands?
HF (High Frequency, 3–30 MHz) bands like 20m and 40m support long-distance skywave propagation. VHF (Very High Frequency, 30–300 MHz) bands like 2m and 6m are used for regional communication and repeaters. UHF (Ultra High Frequency, 300–3000 MHz) bands like 70cm are popular for local communication, especially with handheld radios.