5G frequency bands in the US, from 600 MHz to 47 GHz

Between 2016 and 2022 the FCC sold new mobile licenses in eight auctions that cover the frequencies usually grouped under 5G: 600 MHz, 2.5 GHz, three slices between 3.45 and 3.98 GHz, and millimeter-wave bands from 24 to 48 GHz. Together they drew about $138.8 billion in gross bids, and 58.5% of that came from one auction, the 3.7 GHz C-band sale. Higher frequencies lose more signal over the same distance, and the FCC's public exposure limit is the same 1.0 mW/cm² for every one of these bands except 600 MHz, where it is lower.

The eight auctions and what they raised

Each auction ends with a closing public notice that states the winning bids. The table uses those notices and the FCC's Public Reporting System, which lists the dates each auction opened and closed.

The gap between gross and net is the bidding credits that small businesses and rural carriers can claim. It is small in every row. The bigger gaps are elsewhere, and they come from how two of these auctions were built.

How the spectrum was cleared and sold

Two of the eight were incentive auctions, where the FCC paid existing license holders to give up spectrum. In the 600 MHz sale, TV broadcasters bid in a reverse auction to give up spectrum rights, and those winning bids came to $10,054,676,822. The FCC's closing notice for the incentive auction says at least $7,306,480,884 of the forward-auction money would go to reducing the federal deficit once broadcasters were paid, up to $1.75 billion was set aside to reimburse stations that had to move, and auction costs were covered. Auction 103 worked the same way on a smaller scale: incumbent 39 GHz license holders received $3,084,172,898 in incentive payments, which left net proceeds of $4,474,530,303 according to the Auction 103 notice.

Auctions 102, 103, 107 and 110 ran in two stages, a clock phase and then an assignment phase in which winners bid for specific frequency blocks. The FCC prices each license from the final clock-phase price plus any assignment payment. The C-band clock phase ended January 15, 2021, and the assignment phase closed February 17, with 21 winners taking all 5,684 licenses, per the Auction 107 closing notice.

The 600 MHz band plan that came out of the incentive auction is 70 megahertz of licensed spectrum in seven paired 5-megahertz blocks. Phones transmit at 663-698 MHz and towers at 617-652 MHz, with an 11 MHz gap between the two and a 3 MHz guard band at 614-617 MHz.

The two millimeter-wave sales of 2018 and 2019 ran under limited-information rules. Auction 101 closed on January 24, 2019, but the FCC withheld detailed results, including bidder identities, until the 24 GHz auction ended on May 28. It named the 33 winners of the 28 GHz licenses on June 3, 2019, in notice DA 19-484.

Auction 105 is the odd one. It sold priority access licenses inside the shared Citizens Broadband Radio Service band at 3550-3650 MHz and produced the most licenses and winners of the eight: 20,625 licenses for 228 bidders.

Low, mid and high band in physical terms

On this page, low band means below 1 GHz (the 600 MHz licenses), mid band means the 2.5 to 3.98 GHz auctions, and high band means the millimeter-wave sales from 24 GHz up. The physics behind the labels comes down to wavelength.

Wavelength is the speed of light, about 300 million meters per second, divided by frequency. A 617 MHz wave is 48.6 cm long. A 3.7 GHz wave is 8.1 cm. A 28 GHz wave is about 1 cm, which is where the name millimeter wave comes from.

Between two simple antennas, a shorter wave delivers less power over the same distance. The ITU's standard formula for free-space loss between two simple antennas is 32.4 + 20 log f + 20 log d, with frequency in MHz and distance in km (ITU-R P.525-5). Walls add more. The ITU's building entry loss model, P.2109-2, splits buildings into "traditional" ones and thermally efficient ones with metallized glass or foil-backed panels.

We worked these out from the two ITU formulas; the building values are the model's median at horizontal incidence. An extra 33.1 dB at 28 GHz means about 2,000 times less power arriving over the same distance, before any wall gets involved. That gap fits what the FCC wrote in its 2018 Small Cell Order: to support 5G, providers must build small cells "at a far greater density of deployment than before."

There is a catch the formula itself points to. Its frequency term comes from the shrinking capture area of a simple receiving antenna, which ITU-R P.525 gives as wavelength squared over 4π. A directional antenna of fixed size captures more at high frequency than that simple antenna does, so aiming energy at the user wins part of the loss back. Free space is also the best case. The ITU treats buildings and the clutter around them with separate models, and both add loss.

The exposure limit at each band

The FCC's maximum permissible exposure for the general public is set in 47 CFR 1.1310. From 300 to 1,500 MHz the limit is frequency in MHz divided by 1,500, in mW/cm². From 1,500 MHz to 100 GHz it is a flat 1.0 mW/cm². Both are averaged over 30 minutes or less. Workers who know about their exposure and can control it have a limit five times higher above 1.5 GHz.

The electric-field column uses the plane-wave relation in the FCC's OET Bulletin 65, power density = E² / 3,770 with power density in mW/cm². So 1.0 mW/cm² works out to the square root of 3,770, or 61.4 V/m. The ICNIRP column comes from Table 5 of the 2020 ICNIRP guidelines, which use frequency divided by 200 (in W/m²) up to 2 GHz and 10 W/m² above it. At 600 MHz the FCC value is about a third higher than ICNIRP's. Above 2 GHz the two match.

Two things follow. The limit does not get stricter as 5G moves up in frequency; at 3.7 GHz and 28 GHz it is identical. And the lowest band has the tightest number. OET Bulletin 65 explains that whole-body absorption is most efficient between 30 and 300 MHz, so the limits are strictest there and relax as frequency climbs toward 1.5 GHz.

Auctions since 2022 and the next round

The FCC's public data shows one newer sale: Auction 113, for AWS-3 licenses at 1755-1780 and 2155-2180 MHz, ran from June 2 to June 23, 2026 and drew $3,572,889,200 in gross bids. More is planned. In a September 2026 notice, the FCC said a law signed in July 2025 directs it to repurpose and auction 800 megahertz of spectrum, including 500 megahertz of federal spectrum.

When a new site goes up nearby, you can ask the carrier or the city for its RF evaluation. People also move routers and beds, or buy products such as the sticker packs offered by EMFCALM, which sells EMF stickers for phones and other devices. This page sticks to the bands and the limits.

Whatever the FCC auctions next, the exposure limit for every frequency between 1.5 and 100 GHz stays at 1.0 mW/cm² unless the agency rewrites section 1.1310 itself.