Strip casting is an economically and fast method method to cast thin aluminum sheets at gauges close to the final product gauge. However, the metallurgy of many aluminum alloys is not suitable for strip casting and poor quality may be achieved in the process. The use of a pilot-scale belt-caster for research is expensive, and a single-belt casting simulator has been constructed to study a broad range of casting parameters that affect the cast quality. To achieve a sensible simulation, the conditions should be as identical as possible to a pilot-scale belt-caster. One of the most crucial factors is the heat-flow occurring in the interface between the solidifying metal and its surroundings. Since the flow is hard to measure, a numerical model for interfacial heat flow calculations was created. The model uses a finite difference inverse algorithm for calculations of the heat flow and is written in Matlab. It can be summarized as an automatic IHCP (inverse heat conduction problem) method.