If you plan to live comfortably and need a certain amount of money every month to do so, then how much do you need to save for retirement? If your investing strategy is to pay off debt and hold on to more earning power than it can earn on your account, then it might be smart to figure out what your savings ratio should be. That is, how much of your portfolio will you really need to stay in retirement? Here are three things you can count on in retirement and how to invest to have money left over to live off. 1. Social Security will cover about 70 percent of your average retirement cost. Remember that Social Security is only supposed to replace about 35 percent of your income. While that sounds great, remember that the average Social Security benefit is about $16,500 per year. That means you’ll need about 73 percent of your expected take home to live on. If you’re willing to work a few extra years, you can find ways to increase your take home to 100 percent, and Social Sec