Letâs look at a hypothetical spontaneous chemical reaction: The quantity of usable energy (chemical potential) in a reaction is called the Gibbs Free Energy (DG). DG is the difference between the energy contained in the products of a reaction and the reactants: DG = (energy of products) - (energy of reactants)
That's why some financial experts feel it's more realistic to think in terms of your net income, aka take-home pay, and that you shouldn't use any more than 25% of your take-home on your mortgage payment.
On a monthly basis you would make 12 payments per year. But since there are 52 weeks in the year, paying every two weeks means you will make 26 payments equal to one half of your monthly mortgage payment, or 13 monthly mortgage payments.