Well, this is rich.

Fully two out of three millennials believe that they will become wealthy in the future, compared with just about half of all people, according to a survey of 1,000 people released Thursday by Magnify Money. Other data shows a similar pattern:According to a recent survey by YCharts, an investment research platform, 65% of millennials ages 22-37 say they’ll reach seven-figure wealth by age 45 or sooner. And a survey released earlier this year from TD Ameritrade that found that more than half of millennials expect to be millionaires in their lifetimes, with more than four in 10 saying it’ll happen by 50.

The high visibility of some of these young, uber-rich folks — the Mark Zuckerberg effect, if you will — may help explain why most millennials say they’ll be worth seven figures by 45. And, there is some merit to that: The average age of U.S. investors with $25 million or more is just 47, having dropped 11 years since 2014, according to a survey of 185 Americans by Spectrum Group. While that’s a small sample size, Bloomberg notes that it’s “consistent with other economic research on the top 0.1 percent”.

As many a Gen Xer can attest to though, it is unlikely to be the case for millennials — at least if their current savings rates continue. Fully two-thirds of millennials have nothing saved for retirement, according to a report released this year by the National Institute for Retirement Studies — and 95% are not properly saving for retirement.

“Financial experts recommend that millennials set aside 15% or more of their salary for retirement, which is a much higher rule of thumb than recommendations for previous generations. But we find that millennials’ average retirement savings rate, including employers’ matching contributions, is 10% of their salary,” Jennifer Brown, NIRS manager of research, writes in the report.

All this means it’s pretty unlikely that most millennials will be worth seven figures by the time they’re 45, experts say. “It’s probably not going to happen,” says Sean Brown, the CEO of YCharts.

So why do so many think they’ll be rich? They may be “delusional” about “how much money they are able to save and how much they will be able to earn,” explains Agnes Kowalski, a wealth therapist — who adds this can happen with people of all ages. But she explains that millennials in particular “have incredibly powerful new belief systems about not capping how much money can be earned” as “there are so many careers that were nonexistent even 10 years ago” — which may help explain why they think seven figures is possible.

The FIRE movement (financial independence, retire early) isn’t helping matters either, says Bobbi Rebell, a certified financial planner and host the Financial Grownup podcast. Many of those doing it are millennials, so others who see that may think they can do it too. Another issue is that the millennials who are good at saving may not do an adequate job investing, says Brown — which is what experts say can get you to seven figures quicker. A survey from Bankrate found that “millennials continue to lag behind their elders when it comes to investing in the stock market” with just one third of millennials owning stock, compared to roughly half of Gen Xer and boomers.

Still, the fact that millennials think they might hit seven figures well before their 60s isn’t necessarily a bad thing, says Prudential’s Vice President of Strategic Initiatives Jim Mahaney. Indeed, he says the fact that they think they might hit a goal like that might actually encourage them to save even more.

What’s more, you needn’t have seven figures socked away by 45 to be financially secure. Fidelity recommends that you save four times your annual salary by 45; that means that a person making $75,000 a year should have saved $300,000. By 65 they recommend 10 times your annual salary, or $750,000 in this case.

As for how much total you’ll want to save before you quit working, Kimberly Foss, president and founder of Empyrion Wealth Management and a certified financial planner says to aim for roughly 25 times your desired annual retirement income in savings — though this will vary depending on where you live. So in simple terms, if you want to live on $75,000 a year, you’ll want to have socked away nearly $1.9 million. She adds that you should also be able to live on about 4% of your retirement savings, withdrawn annually. So, if you have $1.9 million socked away, if you withdrew 4% of that a year, you’d get $75,000 to spend.

Foss says that you can check on whether you’re on track with your savings by using tools like this MarketWatch calculator or this Vanguard calculator.

This story was originally published in January 2019 and has been updated.