You should recommend the payoff order based on their interest rates. Also, for completeness as a financial tool, they should be able to plug in savings like retirement savings. A student loan of 8% sounds bad and some people think they should pay it off above all else, but really a 401k where the employer matches 50% of the first 6% you contribute should be the primary focus for the person, since the 50% return is sooo much higher than the 8% interest rate.