• Four in 10 American workers are behind on retirement planning and savings, according to a new CNBC survey.
• Not starting earlier tops Americans' greatest financial regrets.
• "If you do less at 30, you'll still have more at 60 than if you did more at 50," one expert said.

Molly Richardson, 35, regularly contributes to her 401(k) plan, but the structural engineer said she isn't too worried about retirement yet.

"It's always something I felt like I could wait until I'm 50 to figure out," she said.

Like many other working adults, Richardson has more pressing expenses for now, she said, such as the mortgage on her home in Jacksonville, Florida, car loans and student debt.

Still, the married mother of one admits she doesn't have a clear savings goal once those other financial obstacles are out of the way.

"It's hard to estimate how much we are actually going to need," she said. "There are question marks."

In fact, 4 in 10 American workers — 40% — are behind on retirement planning and savings, largely due to debt, insufficient income or getting a late start, according to a new CNBC survey, which polled more than 6,600 U.S. adults in early August.

Older generations closer to retirement age are more likely to regret not saving for retirement early enough, the survey found: 37% of baby boomers between ages 60 and 78 said they felt behind, compared with 26% of Gen Xers, 13% of millennials, and only 5% of Gen Zers over the age of 18.

"There are so many individuals, young, mid-career and deep into their career, that are not saving enough for a healthy and secure retirement," said Jacqueline Reeves, the director of retirement plan services at Bryn Mawr Capital Management.

By some measures, retirement savers, overall, are doing well.

As of the second quarter of 2024, 401(k) and individual retirement account balances notched the third-highest averages on record and the number of 401(k) millionaires hit an all-time high, helped by better savings behaviors and positive market conditions, according to the latest data from Fidelity Investments, the nation's largest provider of 401(k) savings plans.

The average 401(k) contribution rate, including employer and employee contributions, now stands at 14.2%, just below Fidelity's suggested savings rate of 15%.

And yet, there is still a gap between what savers are putting away and what they will need once they retire.

Although many employees with a workplace plan contribute just enough to take advantage of an employer match, "9% [considering a typical 5% savings rate and 4% match], mathematically speaking, will not provide enough in that piggy bank," Reeves said.

"They call it a 'standard safe harbor match' for a reason," she added. "Further in our career, we should be saving 15% to 20%."

"I don't think you ever feel completely caught up," said Lisa Cutter, 56, of Terre Haute, Indiana.

Cutter, who works as an administrator in higher education, explained that it took a while before she could put anything at all toward long-term savings.

"When I first entered the workforce, I was a classroom teacher and I had no money; I was broke," Cutter said.

Now Cutter, who is a single mom, has to prioritize her savings. She relies on the retirement tools and calculators that come with her employer-sponsored plan to stay on track.

"I would probably like to retire around 67," she said.

The retirement savings shortfall

Other reports show that a retirement savings shortfall is weighing heavily on Americans as they approach retirement age.

LiveCareer's retirement fears survey found that 82% of workers have considered delaying their retirement due to financial reasons, while 92% fear they may need to work longer than originally planned. 

Roughly half of Americans worry that they'll run out of money when they're no longer earning a paycheck — and 70% of retirees wish they had started saving earlier, according to another study by Pew Charitable Trusts.

And among middle-class households, only 1 in 5 are very confident they will be able to fully retire with a comfortable lifestyle, according to a recent Retirement Outlook of the American Middle Class report by Transamerica Center for Retirement Studies. The middle class is broadly defined as those with an annual household income between $50,000 and $199,999.

"America's middle class is navigating the turbulent post-pandemic economy and high rates of inflation," said Catherine Collinson, CEO and president of Transamerica Institute. "They are focused on their health and financial well-being, but many are at risk of not achieving a financially secure retirement."

Not saving for retirement earlier is great regret

"If you do less at 30, you'll still have more at 60 than if you did more at 50," said Bryn Mawr's Reeves.

More than any other money misstep, not saving for retirement early enough is the biggest financial regret for 22% of Americans, according to another report by Bankrate. 

But there's no easy way to make up for lost time.

"Inflation and high prices are cited as the biggest obstacle to progress in addressing our financial regrets," said Greg McBride, chief financial analyst at Bankrate.com. "Don't expect an overnight fix."

There are, however, habits that can help.

How to overcome a savings gap

Saving for retirement can be "automated through payroll deduction, direct deposit and automatic transfers," McBride said. "Start modestly and after a couple of pay periods, you won't miss what you don't see."

In addition to automatic deferrals, Reeves recommends opting in to an auto-escalation feature, if your company offers it, which will automatically boost your savings rate by 1% or 2% each year.

Savers closer to retirement can even turbocharge their nest egg.

"Everybody hits 50 and is like, 'wait a minute,'" Reeves said, so "there are other opportunities layered on, because many people are caught at that juncture."

Currently, "catch-up contributions" allow savers 50 and older to funnel an extra $7,500 into 401(k) plans and other retirement plans beyond the $23,000 employee deferral limit for 2024.

It's also important to create a separate savings account for emergency money, Collinson advised, "which will help you avoid tapping into your retirement account when disaster strikes."

Similarly, make sure you are properly insured and employable by staying up to date on the latest technology and training, she added, to avoid potential income disruptions.

"The single most important ingredient is access to meaningful employment throughout your working years," Collinson said.

Most experts recommend meeting with a financial advisor to shore up a long-term plan. There's also free help available through the National Foundation for Credit Counseling.  

REGISTER NOW! Join the free, virtual CNBC's Women and Wealth event on Sept. 25 to hear from financial experts who will help fund your future — whether you are returning to the workforce, starting a new career or just looking to improve your relationship with money. Register here.