Do you have enough for retirement?

Forget the scenes of blissful gray-haired couples prancing on exotic moonlit beaches.

Replace the image with Mother Hubbard digging through the cupboard, or a gray-haired wretch toiling on the job long past 65.

As Americans contemplate their futures, they are a pessimistic crew - more pessimistic than any time in nearly two decades about their prospects for retiring comfortably, according to a study by the Employee Benefit Research Institute, a nonprofit that has been surveying Americans since 1991.

More than 80 percent of working Americans questioned said they were not sure they would have enough money to get through retirement.

Only 18 percent are "very confident" that they will have enough money for a comfortable retirement, according to the national survey. And there has been a sharp erosion in well-being in just a year: When the institute surveyed Americans a year ago, 27 percent were feeling "very confident" they were on track.

The glum mood is widespread, infecting people who have retired as well as those with many years left at work. That is partially a symptom of bad economic times. But it is also time catching up with people who have been more inclined to hope for the best rather than save adequately throughout life.

For example, people who start investing $20 a week on a first job should be able to accumulate close to $1 million by the time they retire, but many procrastinate rather than starting small.

In recent years, though, pollsters have detected a calm among many people already in retirement.

In part, that is because some have pensions that supplement Social Security payments, said Jack VanDerhei, a Temple University professor and a fellow at the research institute, who conducted the study along with Mathew Greenwald & Associates.

Most people retire without calculating what they will need, and fast-rising health-care costs are taking them by surprise, VanDerhei said.

According to the insitute's research, about half of current workers have saved $50,000 or less, and 25 percent said they had saved nothing.

Yet a couple retiring this year should expect to pay $250,000 during retirement for the medical costs Medicare does not cover, VanDerhei said. For couples living to 90, Fidelity has calculated medical costs to be more than $400,000.

"People have a false sense of optimism," VanDerhei said. "It's been showing up for years."

People remain more optimistic than they should about retirement savings, he said. Millions of Americans will be unable to cover basic living expenses with their savings. The employees-research institute has calculated a $45 billion annual shortfall by 2030. And yet Americans still delude themselves, he said.

While only 24 percent of Americans are working for employers that provide pensions - or guaranteed payments in retirement - 86 percent of people think they will somehow end up with a pension, VanDerhei said.

Instead, he said, Americans are going to be on their own to save more money than any previous generation. Those who have 401(k) plans and save on average 7 percent a year should be all right, he said.

But most people do not average that because they change jobs and no longer have 401(k)s or "make mistakes like borrowing from their 401(k)," he said.

In other words, they are right to be worried about their future. And he suggests a first step is doing a simple calculation to determine how they stand. Try the "ballpark estimate" at ChooseToSave.org.