Boston College s Center for Retirement Research recently found that about 64% of Americans aren t saving enough to maintain their standard of living in retirement. Some ways to tell if you re at risk:

The general rule of thumb is that retirees need about 70% to 80% of pre-retirement income to maintain their standard of living. To get a better sense though, consider using software that helps take into account factors like paying college tuition or taking fewer vacations. ESPlanner, which costs $150 and is available at esplanner.com, is one place to start.

Map Out Withdrawals

Many retirees will withdraw 4% of their portfolio in the first year of retirement and adjust that dollar amount each year to account for inflation. Find out if you can live comfortably on that amount plus Social Security payments; if you ve had heavy portfolio losses, consider skipping the inflation bump initially.

Consider Health Care

Because lower-income seniors have their long-term care covered by Medicaid, and wealthier seniors can self-fund their care or buy insurance, those in the middle often have the hardest time paying for such services, a big drain on a nest egg. Anthony Webb of Boston College says non-Medicaid seniors with less than $1 million in assets should plan early for big health costs by cutting expenses elsewhere or delaying retirement.

Figure the Odds

Financial planners can often do modeling that helps calculate the chances you will still have a nest egg to draw from at a given age. Many retirement experts urge workers to wait to retire until their percentage chance of outliving their nest egg drops to 15% or below. To be safe, it s good to assume you ll live to age 90 or 95, especially with longer life spans.