Only 39 percent of investors between the ages of 21 and 50 surveyed in new research from T. Rowe Price said they are confident that they will have enough money for retirement.

And despite understanding the importance of planning for retirement, most (63 percent) of these younger investors have yet to develop a detailed plan for their finances in retirement. Those who have a detailed plan, however, feel significantly more confident about their retirement readiness, with 58 percent believing they will have enough money for retirement.

These findings are highlighted in a T. Rowe Price survey about Individual Retirement Accounts (IRAs) and the investing practices of Generation X, which are people ages 35 to 50 for the purposes of this research, and Generation Y, ages 21 to 34. The study was conducted online in December 2011 by Harris Interactive on behalf of T. Rowe Price among 860 adults aged 21 to 50 who have at least one investment account.

"This research underscores the fact that many more young investors need to get started planning for their retirement, even though the date may be decades away," says Christine Fahlund, senior financial planner with T. Rowe Price.

Looking at some of the components a detailed plan might include, 77 percent of those who have a plan said that it targets an anticipated monthly budget; 84 percent cited having a specific monthly withdrawal strategy; and 78 percent said their plan considers life expectancy and how long their savings might need to last.

Turning to their anticipated finances in retirement, Generation X and Generation Y investors said they expect to receive income from multiple sources: 401(k)s or other workplace retirement plans, 74 percent; IRAs, 65 percent; and non-retirement accounts (e.g., checking, savings, stocks, bonds, mutual funds), 64 percent.

In addition, 63 percent of investors aged 50 and under anticipate receiving Social Security.

"Younger investors' confidence in the Social Security system was surprisingly positive," Fahlund says. "Still, it shouldn't be relied upon too heavily."

When asked at what age they expect to retire, the mean age investors gave was 62. When asked how many years they expect to live in retirement, the mean answer was 22 years. Fahlund says this latter number is a significant underestimate.

"Many people will live well beyond 22 years in retirement," she says. "To be adequately prepared financially and to ensure they don't outlive their money, we suggest that investors annually save at least 15 percent of their salary, including any available employer match, and consider a possible retirement of 30 or more years, to age 95."