Accurate thermodynamic property data of dense fluids and supercritical fluids are important in many scientific investigations and engineering applications. A flow calorimeter has been constructed to measure the isobaric heat capacity of pure fluids and fluid mixtures over a range of temperatures, 25-150 degrees C, and pressures, 1-300 bar. Base measurement accuracy approaches +/- 1% and is limited by precise equipment calibration and refinement of the measurement technique. Validation of the calorimeter's operation was achieved with supercritical carbon dioxide, methanol, and carbon dioxide-methanol mixtures, over a range of conditions from sub-critical to supercritical temperatures and densities, demonstrating the calorimeter's robustness. (C) 2016 Elsevier B.V. All rights reserved.