The Bluetooth SIG, who create the specifications for Bluetooth, have a new Bluetooth Range Estimator that takes into account the environment, transmit power, antenna gain and received gain to provide an estimated range.
There’s also an associated blog post on 3 Common Myths About Bluetooth.
In terms of beacons, the range usually relates to how they are powered. The beacons with smaller CR2032 batteries tend to be designed for ranges up 50m. Larger CR2477 powered beacons usually reach about 100m. AA battery beacons or those with power amplifers reach hundreds of metres. and some USB beacons can reach up to 4Km. These ranges are outdoors. Indoors, there’s often radio reflections and blocking that reduce range. Beacon orientation can also affect range.