To use the Pag-IBIG loan calculator, you'll need to provide essential details like your desired loan amount, loan term, and interest rate. It’s also helpful to know your monthly contribution to Pag-IBIG, as this can affect your loan eligibility. Keep in mind that the calculator gives you an estimate, and actual loan approval and terms will ultimately depend on Pag-IBIG's assessment of your application. For precise requirements and to ensure you have all necessary documents, visit the official Pag-IBIG website or consult with their customer service.