TO FIGURE OUT what you'll need in retirement, you need to know how much you earn now and how much of it you spend. That means you need a monthly financial statement or a budget. To come up with one, write down everything you spend for a month. That includes your rent, mortgage payment, car payment, utilities, food, and so forth. Then spend a few hours going through your checkbook and credit card bills to find those things you missed, like life insurance premiums, vacations, and gifts.
Expenses come in two categories—fixed and discretionary—but some items fall in both camps: clothing, for instance, and food. There are the basics like underwear and orange juice and there are the luxuries like a cashmere sweaters and caviar.
List your sources of income, then split your expenses into fixed and discretionary and list them here.
Look at your fixed expenses. This is the amount that you must cover both now and in retirement.