The area a mobile signal booster can cover depends on two main factors:

Strength of the outside signal: The stronger the cell signal you have outdoors, the larger the area the booster can cover indoors. With a weak outdoor signal, the booster won't have much to amplify.

Booster's gain:  Boosters have a gain rating, which indicates how much they can amplify the signal. A higher gain booster can cover a larger area.

Here's a general idea of coverage areas for different scenarios:

Small homes and offices: Up to 1200 square meters,  we can consider to use the signal booster which the output power from 10dBm to 23dBm.  gain from 65dB to 75dB. 

Large buildings: more than 5,000square meters indoor or outdoor area.  we can consider to use the middle power or macro power signal booster.

Commercial buildings: Even larger areas are achievable, with complex building, such as shopping mall, hospital, high rise building,  we can consider to use the fiber optical system or the distribution antenna system( DAS solution).

It's important to note that these are estimate. The actual coverage area will vary depending on your specific situation.  For a more accurate idea of what a booster can do in your location, it's best to consult with a signal booster provider.(Amplitec)