The present invention is a method for operating a computer-based accounts payable system. The user inputs a bill that includes a billing code. The system then determines whether the billing code is present in the budget database. If the billing code is present in the budget database, the system approves payment of an amount associated with the billing code in the budget database. If the billing code is not present in the budget database, the system approves payment of a budget amount associated with the billing code in a default budget database. In the preferred embodiment, the system also checks whether a particular task has been completed before approving payment of said bill, and checks to insure that a previous bill covering the same task has not been paid previously.