To use the Pag-IBIG multi-purpose loan calculator, visit the official Pag-IBIG Fund website where they provide the necessary tools. Simply input your savings, desired loan amount, and the term of the loan to get an estimate. The calculator will give you an idea of how much you can borrow and the potential monthly repayments. Keep in mind that actual loan approval and terms will depend on Pag-IBIG's evaluation of your individual circumstances, so it’s wise to consult with their representatives or check their official site for specific details.