Build a Wedding Budget Calculator in Wordpress

Hi, I need to get a wedding budget calculator built that will will be linked to each user, where a user can save his calculated costs, come back, login and see his calculated results. A similar calculator to my requirements can be seen here [login to view URL] The calculator is to have the following sections: - Enter Budget- Section for the user to enter his/her budget - Enter number of guest - Various categories such as food and drinks with various sub categories under each category. The proportion of the budgeted amount is then automatically calculated based on the Budget and number of guests is displayed next to the categories. - A column for the user to enter the actual amount for each category -An calculated column to display the variance in budgeted and actual results -A column for the user to enter how much deposit has been paid for each category/sub category -A calculated column showing amount left to be paid. -A section where the user can select/deselect what category to include in the calculation. -Ability to print this The calculator should match the theme of the website and all changes or modifications are only to be made in the CHILD THEME only. Formatting and styling should be such that each column value should be able to accommodate a maximum of 7 digits and the Enter budget section to accommodate 8 digits and number of guest to accommodate 4 digits. The above points are a must and a complete requirement.