Radio frequences are regulated by the FCC in the United States. A GMRS radio may legally be operated only with a FCC license. Per the FCC's GMRS service rules described in 47 C.F.R. Part 95 Subpart E, "Each GMRS station must be identified by transmission of its FCC-assigned call sign at the end of transmissions and at periodic intervals during transmissions except as provided in paragraph (c) of this section. A unit number may be included after the call sign in the identification." If you operate a radio transmitter that requires a license, or use a radio that is authorized for only a specific service for an unauthorized service, you may be fined or imprisoned, and/or the equipment may be confiscated.

• License applicant must be 18 years or older.
• Applicants cannot be a representative of a foreign government.
• No tests or exams are required.
• Applicants pay a $35 license fee (good for 10 years).
• The license can be used by the licensee and immediate family members which include the licensee's spouse, children, grandchildren, stepchildren, parents, grandparents, stepparents, brothers, sisters, aunts, uncles, nieces, nephews, and in-laws. Family members do not need to live in the same household.
• Licensee may may use a combination of portable, mobile, fixed and repeater stations consistent with the operational and technical rules in FCC service rules 47 C.F.R. Part 95 Subpart E.

An individual operating a GMRS station must identify themselves with their FCC-assigned call sign:

• at the end of a transmission or a series of transmissions, and
• at least once every 15 minutes for a series lasting more than 15 minutes.

The call sign must be transmitted:

• in the English language when using voice
• in the international Morse code telgraphy when using an audible tone.

During tranmission, GMRS stations must NOT communicate:

• Messages in connection with any activity which is against Federal, State, or local law
• False or deceptive messages
• Coded messages or messages with hidden meanings ("10 Code" are permissible)
• Music, whistling, sound effects or material to amuse or entertain
• Advertisements or offers for the sale of goods or services
• Advertisements for political candidates or political campaigns
• International distress signals like the word "Mayday" (except to ask for help when on a ship, aircraft or other vehicle is in immediate danger)
• Messages which are both conveyed by a wireline control link and transmitted by a GMRS station
• Messages (except emergency messages) with stations in the Amateur Radio Service, any unauthorized station, or to any foreign station
• Continuous or uninterrupted transmissions except for communications involving the immediate safety of life or property
• Messages for public address systems

A GMRS licensee may use a combination of portable, mobile, fixed and repeater stations that use the 462 to 467 MHz frequency range of the UHF band. 

Portable handheld radios are the most common. Mobile and base station-style radios are normally used for public service and commercial use but can also be used by GMRS stations as long as the radios are certified for GMRS.

While Family Radio Service (FRS) radios use the same frequency range and channels as GMRS radios, GMRS radios have the following advantages:

• More station options. FRS radios are limited to portable handheld models only (no mobile or base stations).
• Increased power. GMRS radios can use up to 5 watts for portable radios (whereas FRS radios are limited to 2 watts) and 50 watts for mobile and base station radios.
• Higher range. GMRS radios have removable antennas so that individuals can replace the default manufacturer antenna with a higher-gain antenna or to aerials mounted remotely on a vehicle, building or tower to enhance signal strength. 
• Extended range using repeaters. GMS radios can use "repeaters" to extend the range of their communications whereas FRS cannot transmit on repeater systems.

If you are wondering which service the model of your radio is made for, locate the FCC ID on the radio and look it up on the FCC website. If your radio does not have an FCC ID, it may not be legal for use on either the GMRS or FRS radio services.

GMRS radios operate on "line of sight" propagation. Essentially, radios/stations can communicate with each other as long as there are no major obstacles in between, such as hilly or mountainous terrain, that would block, deflect, or divert radio signals. Communications are typically direct between radios or transmitted through a repeater station. Typical communication ranges are around:

• 1 or 2 miles for direct communications
• 5 miles for mobile stations with higher antennas
• Hundreds of square miles when using repeaters since individual repeaters can transmit signals up to a 20 mile diameter

GMRS is allotted 30 frequency channels between 462 to 467 MHz with a bandwidth of 25 kHz (20 KHz authorized bandwidth) or 12.5 kHz.

• 462 MHz channels - can be used by GMRS licensees for simplex communication or repeater outputs.
• 467 MHz channels - may only be used as repeater inputs, in conjunction with the 462 MHz channels as outputs.

See this graphical depiction of the GMRS (and FRS) frequency spectrum usage, including bandwidth and maximum power allowances.

After the FCC has granted you a license, you can download an official copy of your license by following these steps:

1. Go to https://wireless2.fcc.gov/UlsEntry/licManager/login.jsp and log in with your FCC Registration Number (FRN) and password.
2. On the left side of the License Manager page, click the “Download Electronic Authorizations” link.
3. In the My Authorizations box at the bottom of the page, select the call sign(s) you wish to download.
4. Then click the Add button to add the call signs to the Authorizations to Download box.
5. Click the Download button in the lower right-hand corner of the page. The download will be automatically converted to a PDF file which you can then print or save to a file.

If you have any further questions on a GMRS license or need additional information, please submit a help request online to fcc.gov/wireless/available-support-services or call (877) 480-3201.