The NIST Chemistry WebBook provides an interactive equation of state calculator for hydrogen. The system provides a full equation of state that can be used over the temperature range 13.957 K to 400 K at pressures to 1210 bar.
This calculator provides isothermal, isobaric, and isochoric properties for hydrogen in units specified by the user. The system was developed by the National Institute of Standards and Technology (NIST).
The equation of state and uncertainties are documented by Younglove, B.A, "Thermophysical Properties of Fluids. I. Argon, Ethylene, Parahydrogen, Nitrogen, Nitrogen Trifluoride, and Oxygen," J. Phys. Chem. Ref. Data, Vol. 11, Suppl. 1, pp. 1-11, 1982.