Abstract: A putting aid device for aiding a golfer in reading a putting green by measuring the direction and amount of slope in a green and indicating to the golfer a putting variance factor for a particular ball lie relative to a ball hole. The putting variance factor produced by the putting aid device corresponds to the distance from a reference putting line to an off-set target point. The putting aid device includes an elongated housing, an elongated bubble vial, and a putting variance scale calibrated with respect to the bubble vial. In use, the putting aid device is selectively positioned on a reference putting line and indicates an off-set target distance. The putting aid device can be used to produce a putting variance chart of the conditions of a green.