Will depend on your power setting as well. Motorola puts it something like this, for their FRS/GPRS radios:
35 miles, mountaintop to valley. Five miles, open water. Three miles, light woods. One mile or less, "neighborhoods", i.e. typical 1-2 story woodframe homes.
Note that UHF is basically line of sight, which puts limits on the range. Line of sight for two radios, six feet above ground, is about three miles even at sea or in the desert. Line of sight between two mountaintops can be 128 miles.
So your range will vary with the power setting, and what stuff is blocking the signal. Your body (a big sack of water) also blocks radio signals pretty well, if it comes between your radio and the "other" one.