Results of a FORTRAN 77 program are presented which follow the harmonic method of tidal height prediction laid down in the Admiralty Tide Tables. Predictions are made for two ports, one with a semidiurnal tidal pattern, the other with a double high water. In the first instance, the port (King's Lynn) is a Secondary Port which follows the calculations from its Standard Port (Immingham). The second set of calculations are for Southampton, which is a Standard Port enabling direct comparison of the results obtained from the FORTRAN 77 program with those given in the Admiralty Tide Tables. Predictions are made for both ports by the graphical method described in the Admiralty Tide Tables as a further test of the program's accuracy. The FORTRAN 77 program enables predictions to be made at timed intervals over the period of a day. It also has an option which predicts both the height values and timing of the high and low tides on the day of prediction.