“A million dollars? Impossible.” That was how Mary Woulf felt when a colleague told her about the power of her company’s 401(k) plan. She was 22, earning $8 an hour and raising a child alone. Three decades later, she retired with a seven-figure balance-a testament to how disciplined saving can take modest beginnings and turn them into extraordinary outcomes.
Nationwide, more Americans are becoming 401(k) millionaires. According to Fidelity, there are more than 512,000 of them at the beginning of 2025-a number that has sharply risen in recent years. Not all of these savers had sky-high salaries or windfall inheritances, but they built wealth through consistency, smart investing, and avoiding costly mistakes.
Their stories and strategies provide a clear roadmap for any mid-career and near-retirement professional who may wonder how to reach that milestone. Here are nine proven approaches they used to grow their retirement accounts into seven figures.
1. Start Early Even with Small Contributions
The sooner retirement savings start; the more compound interest has a chance to work its magic. Mary Woulf started at 22, saving only 3% of her pay because that’s all she could afford-but her employer matched dollar for dollar. Over decades, those small deposits grew and grew exponentially. According to data, a 25-year-old saving $5,000 annually at 7.5% could retire with more than $1.26 million, while someone who starts saving at age 35 would have to save twice as much every year to reach a similar goal. Early contributions, even if modest, lay down the bedrock for long-term growth.
2. Capture Every Employer Match
Employer matches are essentially free money. Joy El-Amin thought she needed to put in 15% of her own salary, and didn’t realize the target included the match. Her mistake had her saving 21% a year, on the road to $1.45 million despite taking eight years off of work. At a minimum, retirement planners say, savers should contribute enough to get the full match in typical plans a 6% employee contribution with a dollar-for-dollar match instantly becomes 12%.
3. Increase Contributions with Every Raise
Bruce Scott couldn’t spare much when he started at Pacific Bell, but he made a promise: every raise would boost his 401(k) contribution. Over 31 years, he grew his rate to 16% of pay, plus a company match, ending with over $1 million from combined pension and 401(k) savings. Incremental increases keep budgets comfortable while steadily raising the savings rate toward the ideal 15% total goal recommended by experts.
4. Max Out When Possible
Those with higher incomes or fewer expenses may accelerate wealth building by pushing the contributions to the legal limit. The 401(k) cap in 2025 is $23,500, with catch-up provisions raising it to $31,000 for those 50 and over and even $34,750 for ages 60–63. Richard Eckman began maxing out at 50 to boost his balance during strong market years. Though that won’t work for everyone, even partial increases during peak earning years can have a quite dramatic effect.
5. Select growth-oriented investments
Stocks have historically returned about 10% a year, and far more than bonds. Well-timed equity purchases-each one of his Costco shares has risen tenfold-helped Eckman. Stocks are “the ultimate compounding machine,” says Morningstar analyst Daniel Noonan, for long-term savers. There’s diversification to consider, too: a mix of large and small U.S. stocks, international equities, and emerging markets reduces risk while keeping growth potential high.
6. Stay the Course Through Market Swings
401(k) millionaire’s rarely panic sell. Eckman inadvertently dodged the 2008 meltdown, reinvested at market lows – though, by most accounts, discipline is key. The stock market goes up and down. Its long-term returns are remarkably good. One stays invested to let compounding recover the losses gradually.
7. Avoid Raiding Retirement Accounts
Pulling money out of a 401(k) early has derailed what could have been decades of growth. Elisa Brown never touched hers, and 25 years of contributions and market gains pushed her over $1 million despite never earning six figures. Withdrawals not only incur taxes and penalties, but they also eliminate future compounded earnings: A $10,000 withdrawal at age 50 could shrink retirement savings by more than $26,000 at age 67.
8. Sequence of Returns Risk
Early retirement market losses can have disproportionately large effects. According to U.S. Bank research, two portfolios with identical average returns can produce radically different results depending on when losses take place. Strategies such as keeping one to two years of expenses in cash or short-term bonds – what advisors call the “bucket approach” – can avoid selling stocks at a loss during downturns, preserving long-term growth potential.
9. Live Below Your Means
Lifestyle choices are a big factor. Brown and her husband, though 401(k) millionaires, still shop at thrift stores and avoid “keeping up with the Joneses.” The shifting of excess money toward retirement accounts, rather than consumption, accelerates savings. A study by T. Rowe Price found that cutting away $550 in monthly expenses and investing it at 7% per year can add about $445,000 to savings over 25 years.
The secret to how these people became 401(k) millionaires doesn’t come from high earners or financial prodigies but from consistent contributions, smart investment choices, and avoiding the urge to take out retirement funds too early. Through this, mid-career and near-retirement professionals will be able to start early, capture employer matches, increase contributions over time, stay disciplined through market cycles, and turn steady habits into substantial wealth with the freedom to enjoy these years ahead.
