Provided are a method, device and system for estimating the location of a user device by using radio signals emitted from access point (AP) devices. In the location estimating method implemented by the user device may include steps of measuring received signal strength of a signal received from two or more AP devices deployed within a specific range, establishing a binding box for each of the two or more AP devices by using the measured received signal strength, and estimating a current location of the user device by using points of contact between the established binding boxes.