Haushaltsrechnung

You can declare your monthly income and expenses in the self-declaration to see how much your monthly disposable income is. This is necessary to understand how much of your income can be allocated to monthly mortgage payments. A general rule of thumb is that no more than 40% of your income should be allocated to your mortgage payments. If your monthly mortgage payments exceed this, you can either pay back the mortgage over a longer period of time by decreasing the annual repayment, or you can choose to take on more risk by taking a shorted fixed interest period. Banks can require such a self-declaration.