A method and system for calculating a heat flow to a sample in a differential scanning calorimeter (DSC). The DSC has a sensor within an enclosure comprising an absolute temperature measurement detector for measuring the temperature of a base position on the sensor, a first differential temperature detector for measuring the temperature difference between a sample position and the base position, and a second differential temperature detector for measuring the temperature difference between a reference position and a sample position. Thermal resistances and heat capacities of the DSC are calibrated. The DSC is operated, and the heat flow to the sample is calculated using a method that accounts for the leakage heat flows.