High Quality Content by WIKIPEDIA articles! Grenzplankostenrechnung (GPK) is a German costing methodology, developed in the late 1940s and 1950s, designed to provide a consistent and accurate application of how managerial costs are calculated and assigned to a product or service. The term Grenzplankostenrechnung, often referred to as GPK, has best been translated as either Marginal Planned Cost Accounting or Flexible Analytic Cost Planning and Accounting.