This paper proposes a software metric for estimating the cost of removing a virus from infected machines. The metric, Virus Removal Cost (VRC), provides an objective estimate of the cost based on two factors: the characteristics of a virus and the computer skills of persons who try to remove the virus from their machine. The metric can give us an insight into the cost of removing a virus, and, hence, produce more reliable data that reduce the deviation of the estimate of the overall damage cost caused by the virus