Cell phones use radio frequencies allocated by the FCC, ranging from 600 MHz to 39 GHz. Low-band frequencies (600-850 MHz) travel farther and penetrate buildings better, while high-band (24-39 GHz) offers ultra-fast speeds over short distances.
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Cell phones communicate with towers using specific radio frequencies licensed by the Federal Communications Commission (FCC). These frequencies, measured in hertz (Hz), range from hundreds of megahertz (MHz) to tens of gigahertz (GHz). In the United States, the FCC auctions blocks of spectrum to carriers, who then deploy their networks on those bands. Every modern smartphone supports multiple frequency bands to work with different carriers and technologies. As of 2026, the typical phone includes support for 30 or more distinct frequency bands across 4G LTE and 5G NR standards.
Low, Mid, and High-Band Breakdown
Cell phone frequencies are grouped into three categories based on their physical properties:
- Low-band (600–850 MHz): Excellent range and building penetration. Used for widespread coverage in rural and suburban areas. Key bands include 600 MHz (Band 71) and 850 MHz (Band 5).
- Mid-band (1.7–2.5 GHz): Balances speed and coverage. Includes AWS (1.7/2.1 GHz), PCS (1.9 GHz), and the 2.5 GHz band popular for 5G mid-band deployments.
- High-band (24–39 GHz, also called mmWave): Very high capacity and low latency but short range. Requires line-of-sight and dense small-cell deployments. Used in stadiums and urban corridors.
The following table summarizes key allocated bands:
| Band Category | Frequency Range | Common Uses |
|---|---|---|
| Low-band | 600–850 MHz | 4G LTE, 5G NR (coverage) |
| Mid-band | 1.7–2.5 GHz | 4G LTE, 5G NR (speed & coverage) |
| High-band (mmWave) | 24–39 GHz | 5G NR (ultra-fast, short range) |
How Frequencies Affect Coverage and Speed
The frequency directly determines how far a signal travels and how much data it can carry. Lower frequencies (like 600 MHz) can cover miles and pass through walls, but their data speeds top out around 100–200 Mbps. Higher frequencies (like 28 GHz) deliver multi-gigabit speeds but may only reach a few hundred feet. Carriers mix bands to create a seamless experience: low-band for wide coverage, mid-band for everyday speeds of 200–800 Mbps, and high-band for short-range bursts above 1 Gbps. This layered approach, known as spectrum aggregation, is why your phone can show 5G even when connected to a low-band frequency.
4G LTE vs 5G Frequency Differences
4G LTE primarily uses frequencies below 2.6 GHz, with many bands in the 700 MHz, 850 MHz, 1.9 GHz, and 2.1 GHz ranges. 5G NR expands into higher frequencies—up to 52 GHz for FR2—and introduces new bands like n71 (600 MHz), n78 (3.5 GHz mid-band), and n260 (39 GHz mmWave). 5G also supports wider channel bandwidths (up to 400 MHz in mmWave) compared to LTE’s maximum 20 MHz per carrier. This allows 5G to deliver dramatically higher peak speeds. However, 5G devices must be backward-compatible: every 5G phone sold in the U.S. also supports all relevant 4G LTE bands.
How to Find Your Phone’s Supported Frequencies
To see which frequencies your phone can use, check the device specifications under “Network” or “Bands.” The FCC ID database (fccid.io) lists each phone’s tested frequencies. Alternatively, dial *#*#4636#*#* on many phones to view the band settings menu. Knowing your phone’s band support matters when choosing a carrier, especially if you travel frequently or rely on rural coverage. Most unlocked phones sold after 2023 include at least 4G bands 2, 4, 5, 12, 13, 66, and 71, plus 5G bands n41, n71, n77, and n260—covering both major networks.