Free Qibla Finder, points you to Qabe in Mecca, where Muslims must turn to before they pray. Application tries to fix your location on the world using one of GPS sensor, wireless networks or cell data. Whichever fixes with more accurate than the value set in the application settings is used. After that application calculates magnetic declination using algorithm and coefficients supplied by World Magnetic Model. By calculating magnetic declination, application now knows how many degrees is Magnetic North is wrong from Geographic North. At last, using compass, it shows you the direction that Qibla resides.
If you are not willing to fix your location for some reason, you can also select where you are from the database that resides in the application. All the towns that has population more than 15 thousands as of 2012 are listed in the included database.
In order to conserve battery and speed up finding direction, you can select your location from database. If you are not very close to Qabe, e.g. you are not in the city of Mecca, frankly, your error will be negligible.
If you use one of the location fixing methods, after a fixation on your location occurs, application will try to calculate nearest five town centers to the fixed location. So that you should check and see if application reads your location right.
Magnetic declination is a function of time and space. It changes by traveling on Earth or by time. A prediction is done by National Oceanic and Atmospheric Administration of USA. Their coefficients and formulation is included in the application. These predictions will expire on 2020. So when we get close to 2020, you will need to update the application.