"How far will that radio go?"
"What type of radio should I get for most range?"
These simple questions often lead to complex answers because so many factors influence the distance of radio communications. To simplify, the following charts show how many miles you can usually communicate over normal terrain in suburban or rural areas with different types of radios, power levels, and station configurations. The graphs compare the most commonly available 2-way radios such as ham, CB, FRS, MURS, and GMRS. Some radio gear advertisements tout the maximum possible distance in perfect conditions, an often misleading specification. In the real world, people want to know the normal dependable average range of a radio. Here it is:

The above graph shows the distance range between two base stations using a basic antenna mounted on the roof of a suburban house with a height of about 20ft above ground level. Communication distance can be greatly improved over this by advanced gain antenna systems or a high pole or a tower. This estimate is based upon radio-to-radio direct communications without the use of a repeater.

The above graph shows the distance range between a mobile vehicle with a basic vehicle antenna, communicating with a base station using a basic antenna mounted on the roof of a suburban house. Communication distance can be greatly improved over this by advanced gain antenna systems or a high pole or a tower at the base station. The distance can be adversely affected by interference from the vehicle engine; further distance can be achieved by parking on a hilltop or open area and shutting off the vehicle. This estimate is based upon radio-to-radio direct communications without the use of a repeater.   

The above graph shows the distance range between two mobile vehicles with basic vehicle whip antennas. Communication distance can be somewhat improved (25%to 50% further) over this on VHF and UHF by the use of a gain antenna. The distance can be adversely affected by interference from the vehicle engine; further distance can be achieved by parking on a hilltop or open area and shutting off the vehicle. This estimate is based upon radio-to-radio direct communications without the use of a repeater.   

The above graph shows the distance range between a pedestrian with a whip antenna and a mobile vehicle with a basic vehicle whip antenna. HF backpack radios, HF packs, CB backpack radios, or manpack radios are compared with Handy Talkies, Walkie Talkie, or HT radios. Communication distance can be somewhat improved (25%to 50% further) over this on VHF and UHF by the use of a gain antenna on the vehicle. Distance on VHF will be somewhat less if a smal rubber ducky antenna is used on the pedestrian radio instead of a full size antenna. The use of a counterpoise radial wire on the pedestrian radio improves distance. This estimate is based upon radio-to-radio direct communications without the use of a repeater.