Roof Calculator is a calculator designed to help roofers. The program allows the calculation of four types of roofs: single-pitched, gable, attic and hip. Program functions: calculating the roof area, calculating the roof angle, calculating the length of the rafters, calculating the rows of rafters taking into account the pediment and overhangs, calculating the pitch of the rafters, calculating the number of rafters taking into account the given length of the edged board, calculating the sheathing taking into account all overhangs and rows of rafters, calculating the rows lathing, calculation of the amount of lathing taking into account the given length of the edged board, calculation of the roof material with graphic information, installation instructions, graphic image of the future roof. The finished project can be saved as a pdf file with convenient storage and viewing. Other types of roofs will be added in the process. All necessary information will be added upon request