BLE Bluetooth Low Energy Power, Sensitivity, & Range

Bluetooth low energy operates in the 2.4 GHz ISM (Industrial Scientific Medical) band (2402 MHz - 2480 MHz), which is license-free in most countries. The recent changes in the Bluetooth and regulatory standards allow Bluetooth Smart devices to transmit up to 100 mW (20 dBm) transmit power. However not all countries allow the 100 mW transmission power to be used because Bluetooth low energy radio can drop down to two RF channels when there is significant interference.

See also:
Bluetooth Low Energy weather station
Getting Started with the BlueGiga BLE112 Bluetooth Low Energy module
Silicon Labs - UG103.14: Bluetooth® LE Fundamentals

Summary

bluetooth distance