This work presents a predictive calculation tool for the wear of dry-running piston rod sealing elements, called “packing rings”, which are placed into the pressure packing of reciprocating compressors. Packing rings are performance determining components in two ways: i) they are key to an efficient operation during their lifetime and ii) they cause very expensive downtime and loss of production if failing unexpectedly. The rings’ duty is to seal the compression chamber towards the ambient. “Dry-running” applications are tribologically most challenging because lubrication must not be used. Due to their working principle the packing rings are inevitably subject to wear. Proper sealing performance over the rings’ lifetime is only achieved by geometrically compensating wear. Time and cost intensive laboratory testing is important and industry standard, but several quantities of interest (stress, strain, contact pressure, wear pattern, etc.) are hardly or not at all accessible via experiments. Finite element (FE) calculations allow to gain insight into these quantities and their evolution with time, which is key to better understanding and further improving packing rings. The modelling and the simulation procedure are compared against analytical models and purpose-developed experiments proving the reliability and predictive capabilities of the numerical approach. This FE tool allows for the first time to bridge the gap between laboratory testing and real-world applications.