Radio frequencies are the range of electromagnetic wave oscillation used for wireless communication and broadcasting, spanning from 3 Hz up to 300 GHz. This band sits within the broader electromagnetic spectrum, alongside microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays — radio waves specifically have the longest wavelengths in that spectrum, ranging from a few centimeters up to thousands of kilometers.
Who Manages This Spectrum
The International Telecommunication Union – Radiocommunication Sector (ITU-R) is responsible for allocating radio frequencies globally. Individual bands are assigned to specific purposes — AM radio, FM radio, television broadcasting, cellular networks, Bluetooth, walkie-talkies, satellite communication, air traffic control, emergency responder networks, and military use, among many others. Some bands, notably the Industrial, Scientific, and Medical (ISM) band and the Unlicensed National Information Infrastructure (UNII) band, are license-free — anyone can operate a device there without a spectrum license, which is exactly why Wi-Fi, Bluetooth, and many other consumer wireless devices are built around these specific bands.
This allocation matters practically, not just administratively: without a coordinated global body assigning specific bands to specific purposes, a device built for one country’s cellular network could easily interfere with another country’s aviation or emergency-service radio simply by using an overlapping frequency. The ITU’s framework is what allows a manufacturer to build one Wi-Fi chipset that works consistently across most of the world’s countries, since the 2.4 GHz and 5 GHz bands are internationally harmonized for exactly this kind of unlicensed use.
The Complete ITU Radio Frequency Band Table
This is the actual, verified ITU designation for every band from the lowest usable radio frequency up through the boundary where radio gives way to the next region of the electromagnetic spectrum:
| Band | Name | Frequency Range | Wavelength Range |
|---|---|---|---|
| ELF | Extremely Low Frequency | 3 Hz – 30 Hz | 100,000 km – 10,000 km |
| SLF | Super Low Frequency | 30 Hz – 300 Hz | 10,000 km – 1,000 km |
| ULF | Ultra Low Frequency | 300 Hz – 3 kHz | 1,000 km – 100 km |
| VLF | Very Low Frequency | 3 kHz – 30 kHz | 100 km – 10 km |
| LF | Low Frequency | 30 kHz – 300 kHz | 10 km – 1 km |
| MF | Medium Frequency | 300 kHz – 3 MHz | 1 km – 100 m |
| HF | High Frequency | 3 MHz – 30 MHz | 100 m – 10 m |
| VHF | Very High Frequency | 30 MHz – 300 MHz | 10 m – 1 m |
| UHF | Ultra High Frequency | 300 MHz – 3 GHz | 1 m – 10 cm |
| SHF | Super High Frequency | 3 GHz – 30 GHz | 10 cm – 1 cm |
| EHF | Extremely High Frequency | 30 GHz – 300 GHz | 1 cm – 1 mm |
| THF | Tremendously High Frequency | 300 GHz – 3 THz | 1 mm – 0.1 mm |
Every band boundary in this table sits at a power-of-ten frequency mark — 3, 30, 300 — which is why the wavelength range shrinks by roughly a factor of 10 with every step down this table.
This is the actual ITU-R nomenclature (formally defined in ITU-R Recommendation V.431), and it’s worth memorizing in this exact order, since the sequence itself — extremely, super, ultra, very, low; then low, medium, high; then very, ultra, super, extremely, tremendously, high — is symmetric around the middle bands and easy to get subtly wrong if you’re recalling it from memory rather than checking against a reference. This is precisely the kind of table where a single shifted row can silently propagate errors through everything built on top of it, which is exactly what happened in earlier, uncorrected versions of this reference.
Where Common Wireless Technologies Actually Sit
Most consumer wireless technologies cluster in the UHF, SHF, and lower EHF bands:
| Technology | Frequency | ITU Band |
|---|---|---|
| Wi-Fi (802.11b/g/n) | 2.4 GHz | UHF |
| Wi-Fi (802.11a/n/ac) | 5 GHz | SHF |
| Wi-Fi (802.11ad) | 60 GHz | EHF |
| Bluetooth | 2.4 GHz | UHF |
| 4G/5G cellular (sub-6) | Roughly 600 MHz – 6 GHz | UHF / SHF |
| 5G mmWave | 24 GHz and above | EHF |
Wi-Fi’s 2.4 GHz operation falls in the license-free ISM band; its 5 GHz operation falls in the UNII band — both license-free specifically because regulators carved out these ranges for exactly this kind of unlicensed consumer device use. 802.11ad, the least common of the three listed here, uses the 60 GHz band specifically to get access to much wider channels than either 2.4 or 5 GHz can offer, at the cost of very short range and poor penetration through walls — a direct trade-off of the same kind covered for mmWave 5G in the wireless technologies article.
Why Lower Frequencies Travel Farther, and Higher Frequencies Carry More Data
This is the fundamental trade-off underlying almost every wireless technology decision, worth understanding independent of any specific standard:
- Lower frequencies (VLF through HF) travel extremely long distances, in some cases via ionospheric reflection that lets a signal bounce around the curvature of the Earth — this is why VLF is historically used for submarine communication (its long wavelength penetrates seawater to a meaningful depth) and why HF supports long-distance amateur and aviation radio. The trade-off is bandwidth: these bands can only carry a limited amount of data per second, since the available spectrum at these frequencies is narrow relative to higher bands.
- Higher frequencies (SHF and EHF) support much higher data rates because more spectrum bandwidth is physically available up there, but they travel shorter distances and are increasingly blocked by physical obstacles like walls, rain, and foliage.
This is exactly why 5G networks combine multiple frequency ranges rather than picking one: lower sub-6 GHz spectrum for wide coverage, and mmWave EHF spectrum for very high throughput in specific, dense locations where its short range isn’t a practical limitation.
Worked Example: Classifying a Frequency
Given any specific frequency, classifying it correctly just means checking which decade it falls into. Take 2.4 GHz, Wi-Fi’s most common band:
- 2.4 GHz = 2,400 MHz
- The UHF band covers 300 MHz to 3 GHz (3,000 MHz)
- 2,400 MHz falls between 300 and 3,000 MHz, so 2.4 GHz is UHF — matching the table above.
Same check for 5 GHz:
- 5 GHz = 5,000 MHz = 5 GHz
- The SHF band covers 3 GHz to 30 GHz
- 5 GHz falls between 3 and 30 GHz, so 5 GHz is SHF — again matching the table.
And for 60 GHz:
- The EHF band covers 30 GHz to 300 GHz
- 60 GHz falls in that range, so 60 GHz is EHF.
This same check works for any frequency: find which two power-of-ten boundaries it sits between, and that identifies the band — no need to memorize which specific technologies sit where, if you can reliably do this calculation from the boundaries themselves.
Frequently Asked Questions
What is the actual frequency range of radio waves?
3 Hz to 300 GHz, as defined by the ITU. This entire range is subdivided into twelve named bands — ELF, SLF, ULF, VLF, LF, MF, HF, VHF, UHF, SHF, EHF, and THF — each spanning exactly one order of magnitude in frequency.
What frequency does Wi-Fi actually use?
2.4 GHz for older and widely-compatible Wi-Fi standards (802.11b/g/n), which falls in the UHF band. Newer standards also use 5 GHz (802.11a/n/ac), in the SHF band, and 802.11ad specifically uses 60 GHz, in the EHF band, for short-range, very high-bandwidth links.
Why are the 2.4 GHz and 5 GHz bands unlicensed?
Regulators specifically designated the 2.4 GHz range as part of the ISM (Industrial, Scientific, and Medical) band and the 5 GHz range as part of the UNII (Unlicensed National Information Infrastructure) band, allowing consumer devices to operate there without an individual spectrum license — this is exactly what makes Wi-Fi and Bluetooth practical for ordinary consumer use.
Why do higher frequencies carry more data but travel shorter distances?
More usable bandwidth is physically available at higher frequencies, which is what enables higher data rates. But higher-frequency signals are also more easily absorbed or blocked by physical obstacles — walls, rain, foliage — and don’t benefit from the ionospheric reflection that lets much lower frequencies travel extremely long distances around the curvature of the Earth.
Is there a real ITU band beyond EHF?
Yes — THF (Tremendously High Frequency), covering 300 GHz to 3 THz. Beyond THF, radio frequencies transition into the infrared portion of the electromagnetic spectrum, at which point the ITU’s radio band naming convention stops applying entirely.
How is the ITU different from bodies like the FCC or IEEE when it comes to frequency allocation?
The ITU-R sets the overall global framework for how frequency bands are named and broadly allocated across regions. National regulators, like the FCC in the United States, handle the specific licensing and enforcement of spectrum use within their own country, working within the ITU’s broader international framework. The IEEE, separately, defines the specific technical standards — like 802.11 for Wi-Fi — that describe exactly how a given technology operates within whatever frequency band it’s been allocated.
Conclusion
The ITU’s radio frequency band chart is a straightforward, decade-by-decade division of the spectrum from 3 Hz to 300 GHz — ELF through THF — with every boundary sitting exactly at a power of ten. Getting this table right matters beyond memorization: it’s the reference point for understanding why VLF submarine communication, HF long-distance radio, UHF Wi-Fi, and EHF millimeter-wave 5G all behave so differently despite all being “radio waves” in the broadest sense. The band a technology occupies determines its fundamental range-versus-bandwidth trade-off long before any specific standard or protocol gets layered on top of it.
