NEW YORK — Four out of five workers aren't saving enough to maintain their lifestyle after retirement, with women being at a disadvantage because of their longer life spans and lower pay, according to a study released Tuesday.

On average, employees are projected to replace just 85 percent of their income in retirement, compared with the 126 percent they would need when factoring in inflation, longer life spans and medical costs, the study by Hewitt Associates found.

The study looked at the projected retirement levels of nearly 2 million current workers of varying ages at 72 large U.S. companies and used actual employee balances.

People would need to save from 10 percent to 12 percent of their income throughout their career to keep up the same lifestyle after retirement, said Alison Borland, one of the study's authors.

The study found just 19 percent of workers were on track to do so.

These workers typically started saving early in their career — sometime in their 20s — and didn't cash out the savings when they switched jobs, Borland said.

"Once you get into your 30s and 40s and later, it gets very difficult to start saving enough," she said.

Most people contribute an average of 8 percent of their income into savings plans, she said. Some may also have pension or profit-sharing plans to boost savings, she added.

Of those studied, more than 1.2 million employees (67 percent) are expected to have less than 80 percent of what they would need to maintain their lifestyle at retirement.

Those who don't contribute to 401(K) plans face an even bleaker future. These workers will likely only be able to provide less than 40 percent of their projected needs, according to the study.

While the same percentage of men and women contributed to retirement plans, women faced an 8 percent greater shortfall in savings.

The biggest reason for the gap was a disparity in pay. Women earned an average of $57,000, while men earned an average of $84,000. Since medical costs are not adjusted by gender, women's savings didn't go as far.

Women are also expected to live longer than men, meaning they have to spend at a lower rate while also covering medical costs for a longer period. Finally, women tend to be in and out of the work force more frequently for family reasons, leading to breaks in savings.

Women also started saving later and at a lower rate, the study found.

The result was that women had accumulated 84 percent of pay, while men of the same age accumulated 101 percent.

The Hewitt study projects workers will need to save enough to receive 126 percent of their income each year to maintain their standard of living, thanks to rising medical costs, inflation and longer life spans.

Traditionally, it was thought people needed to replace about 80 percent of their income to maintain their lifestyle after retirement. That level assumes workers will be paying fewer taxes and will no longer need to save for retirement.

It also assumes people have paid off mortgages and debt, which will not be the case for many.

"Many of us will have years left on our mortgages when we retire," said Sheryl Garrett, founder of Garrett Planning in Shawnee Mission, Kan.

Many people are also forced out of work sooner than 65.

Staying in the work force longer can have a dramatic impact on retirement savings, Garrett said. Working even just a few extra years can make a difference, she said.

"It's that many fewer years you're drawing on your nest egg, and that many more years that you're saving," she said.