You have a 3% 15-year mortgage, $2,200 monthly payment. The 30-year mortgage is $1,300 a month.

Assume you take the 30-year mortgage and invest the $900 a month you would have extra from not taking the 15-year mortgage. You average a nominal 7% annually. What amount would you have at the end of 30 years? Remember payments dictate the units.

On the other hand, if you take the 15-year mortgage, at the end of 15 years you could invest $2,200 a month for the following 15 years (you have no mortgage payment at that point) How much would you have doing it this way if you earned a nominal 7% annually?

Assuming you don not “waste” (beer, coffee, bad movies although some may not consider this waste) with the $900 a month extra from taking the 30-year mortgage, can taking the 30-year mortgage make financial sense?