Ham Radio Frequency Calculator
Amateur (ham) radio operators use a range of frequency allocations spanning from the low-frequency 160-metre band up through microwave frequencies above 1 GHz. Each frequency has a corresponding wavelength determined by the speed of light: wavelength in metres equals 300,000,000 divided by the frequency in hertz. In the United States, the FCC allocates these bands under Part 97 of the Code of Federal Regulations and assigns them to license holders at the Technician, General, and Amateur Extra classes. Different bands suit different purposes: lower HF bands (160m, 80m, 40m) are reliable for regional and night-time long-distance contacts; mid-HF bands (20m) provide worldwide propagation through most of the 11-year solar cycle; upper HF bands (10m, 12m, 15m) open for spectacular long-distance contacts at solar maximum; and VHF/UHF bands (2m, 70cm) are primarily used for local FM repeater operation and satellite work. Enter any frequency in MHz below to calculate its wavelength and identify which amateur band (if any) it falls within.
How wavelength is calculated
The relationship between wavelength and frequency is: wavelength (metres) = speed of light / frequency (Hz). Using the rounded constant of 300,000,000 m/s:
λ (m) = 300,000,000 / (f_MHz × 1,000,000)
λ (m) = 300 / f_MHz
Worked example: 14.225 MHz (20m band phone sub-band)
- Wavelength = 300 / 14.225 = 21.09 m
- Falls in the 20m band (14.000 to 14.350 MHz)
- Primary DX band: reliable worldwide propagation
US amateur radio band reference (FCC Part 97)
All 16 US amateur allocations from HF through microwave, with wavelength, frequency range, and primary propagation characteristics.
| Band | Frequency range (MHz) | Wavelength (m) | Primary uses and propagation |
|---|---|---|---|
| 160m | 1.8 to 2 | 157.89 | Ground wave and night-time sky wave, regional to DX at night |
| 80m | 3.5 to 4 | 80.00 | Regional day, DX at night via sky wave |
| 60m | 5.3305 to 5.4035 | 55.90 | Channelized; regional sky wave |
| 40m | 7 to 7.3 | 41.96 | Reliable regional and DX; excellent night-time DX |
| 30m | 10.1 to 10.15 | 29.63 | CW and digital only; good DX propagation |
| 20m | 14 to 14.35 | 21.16 | Primary DX band; reliable worldwide propagation |
| 17m | 18.068 to 18.168 | 16.56 | Excellent DX; less crowded than 20m |
| 15m | 21 to 21.45 | 14.13 | DX when solar cycle active; poor at solar minimum |
| 12m | 24.89 to 24.99 | 12.03 | DX at solar maximum only |
| 10m | 28 to 29.7 | 10.40 | Local and DX; FM repeaters at top of band |
| 6m | 50 to 54 | 5.77 | Magic band; sporadic-E, aurora, and meteor scatter |
| 2m | 144 to 148 | 2.05 | Primary VHF band; local FM repeaters |
| 1.25m | 219 to 225 | 1.35 | Less common; some repeaters |
| 70cm | 420 to 450 | 0.69 | Local FM repeaters; satellites; ATV |
| 33cm | 902 to 928 | 0.33 | Experimental; ISM band overlap |
| 23cm | 1240 to 1300 | 0.24 | Microwave; EME (Earth-Moon-Earth) |
Ham radio: frequently asked questions
What license classes are required for ham radio in the United States?
The FCC issues three classes of amateur radio license in the United States under Part 97: Technician, General, and Amateur Extra. The Technician license is the entry level and grants full privileges on all amateur bands above 30 MHz (VHF and UHF) plus limited HF privileges. The General class adds significant HF band access. The Amateur Extra class grants full access to all US amateur allocations. Each class requires passing a written examination. No Morse code test has been required since 2007.
How do HF propagation conditions affect which bands to use?
HF propagation depends heavily on the solar cycle, time of day, and season. Higher-frequency bands (10m, 12m, 15m) require high solar activity (solar maximum) for reliable long-distance sky-wave propagation. The 20m band offers reliable worldwide propagation across most of the solar cycle. Lower-frequency bands (40m, 80m, 160m) are best for regional night-time contacts via sky wave and ground wave. DX operators track solar flux index (SFI) and K-index to predict conditions.
What is FCC Part 97 and why does it govern ham radio?
FCC Part 97 (Title 47, Code of Federal Regulations, Part 97) is the set of regulations governing the Amateur Radio Service in the United States. It defines license classes, frequency allocations, power limits, emission types, operator responsibilities, and prohibited uses. Part 97 is administered by the FCC Wireless Telecommunications Bureau. Amateur radio is unique in that it permits two-way communications on shared frequencies for education, emergency communications, and technical experimentation.
What is the difference between a simplex and a repeater frequency?
Simplex operation uses a single frequency for both transmit and receive; both stations transmit and receive on the same frequency in turn. Repeater operation uses two frequencies: a user transmits on an input frequency and the repeater retransmits on an output frequency (the offset). On 2m the standard offset is plus or minus 600 kHz; on 70cm it is plus or minus 5 MHz. Repeaters extend the range of handheld and mobile stations by retransmitting from a high location.
How do I get an amateur radio license in the United States?
To obtain a US amateur radio license, pass a written examination administered by a volunteer examiner (VE) team. The Technician exam (Element 2, 35 questions) and General exam (Element 3, 35 questions) are available at most test sessions. The Amateur Extra exam (Element 4, 50 questions) requires passing the lower-level exams first. Examinations are based on publicly available question pools maintained by the National Conference of Volunteer Examiner Coordinators (NCVEC). Study guides and practice exams are freely available online. After passing, the FCC issues the license and calls sign, typically within a few days.
Official sources
- FCC Part 97 (Amateur Radio Service): fcc.gov/wireless/bureau-divisions/mobility-division/amateur-radio-service
- ARRL (American Radio Relay League): arrl.org
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology. Frequency allocations are subject to change; verify with current FCC rules.