With mortgage rates, there is a range of rates that should be quoted. The lower rates have a higher cost. With a no-cost mortgage, the costs are paid by the yield spread premium (paid by lender). If you divide the difference in payment into the difference in cost to get the loan, you will get the break-even point. With a 15-yr mortgage, the break-even point is almost always > than the amortized period of the loan -- you are usually better off taking the higher rate and not paying closing costs.