Systems, methods, and devices for providing an adjusted yardage recommendation (AYR) to a golfer prior to a golf shot. AYRs are determined based on predicted golf ball trajectories that are modeled from a golfer's golf ball launch data, using non-classical mathematical approximation methods. Each of the modeled trajectories are unique, and result in personalized AYR values that are personalized to each individual golfer, even where two golfers hit a ball with the same club the same distance while having two different ball flights. Devices that can perform the methods of the present invention include rangefinder devices and/or portable computing devices, such as a smartphone. Systems can include a rangefinder device and a portable computing device, in which the rangefinder device determines the line-of-sight distance and angle of elevation to a target and communicates the same to the portable computing device, which calculates the AYR.