- the specific 802.11 protocol employed
- the overall strength of the device transmitter
- the nature of obstructions and interference in the surrounding area
Another rule of thumb holds that the effective range of 802.11a is approximately one-third that of 802.11b/g/n.
Both of these rough estimates represent the high end of the range seen in practice. Obstructions in home such as brick walls and metal frames or siding greatly can reduce the range of a Wi-Fi network by 25% or more. 5 GHz Wi-Fi connections like those of 802.11a are more susceptible to obstructions than more the more common 2.4 GHz connections. Interference from microwave ovens and other equipment also affects Wi-Fi network range. Because 2.4 GHz radios are commonly used in consumer gadgets, 802.11b/g/n protocols are generally more susceptible to interference inside residential buildings.
Building a network with multiple wireless routers (or access points) can extend a Wi-Fi network to much longer distances. Though the cost can be high, wireless hotspots spanning several square miles (kilometers) have been built in some cities.