A CPR feedback system, software and methods are provided. A top height sensor can be used to track the height of the patient's chest during the CPR chest compressions, by detecting a top aspect of its location. A depth module may generate, from a detected top aspect, a depth value for a depth reached by a current compression. A counter may determine a compressions number, e.g. for the current compression. A memory may store a depth variable that can return different target values for the target depths of individual compressions. A user interface has an output device that may output an indication for the rescuer, which reflects how well the depth value of the current compression matched a corresponding target value for it. The target values may be set so as to follow a preset profile, or change according to optional measurements of force and other parameters.
