According to a recent report from Fidelity Investments, the average 401(k) balance in the second quarter of 2022 was $103,800. Because of a tough market, that average is down 17% from the prior year.

Occasional backward momentum is a normal occurrence for investors. But knowing the stock market has downturns doesn't make it easier to manage. Most savers (including me) see their retirement balances dip and wonder if they'll ever catch up.

To quiet those nervous thoughts, let's walk through what it takes to turn your $100,000 balance into $1 million by the time you retire.

Monthly investments to retire a millionaire

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The table below shows the estimated monthly investment you'd need to grow a $100,000 nest egg to $1 million, based on the years left until retirement.

Years Until Retirement

Starting Account Balance

Additional Monthly Investment

Balance at Retirement





















Table data source: Author calculations via

The numbers assume the funds are invested to grow at 7% annually on average. As you know, the stock market doesn't behave uniformly from one year to the next. Fortunately, an average growth rate allows for ups and downs in individual years, as long as they balance out over time to 7%.

That 7% is in line with the stock market's historic long-term performance, net of inflation. It's an appropriate rate to use for projections covering 15 years or more. The longer the time frame, the better the chance you have of meeting or beating a 7% average growth rate.

Note that all five scenarios also assume you invest continually, whether the market is up or down.

Time is your friend

You can see from the numbers that growing $100,000 into $1 million is easier with a longer timeline. If you've already saved $100,000 and you're not retiring for 35 years, for example, you may not need additional contributions to reach the millionaire milestone. You could probably wait and watch price appreciation -- and, where applicable, reinvested dividends -- help add a zero to your retirement balance.

In time frames shorter than 25 years, the required monthly investment ramps up quickly. At 15 years, for example, the monthly investment exceeds the maximum 401(k) contribution limit, including catch-up contributions. You'd have to save excess funds in another account.

When your timeline is short

If your retirement timeline is on the short side, you could face some tough decisions, especially if you can't afford a monthly contribution of $2,000 or more.

Go through your expenses and cut back where you can. Raise your contribution to the highest level you can afford. Then, plan on reassessing your situation every year.

The math might not be on your side today, but that can change. You could see quick growth on the other side of this down market, for example. If you raise your contributions now, your savings outlook might seem much better in a few years.

Invest early and often

Investing early and often is the key to adding zeros to your retirement balance. Whether you want to go from $100,000 to $1 million or $500,000 to $5 million, the process is the same: Maximize your monthly contributions and keep investing for decades, whether the market is up or down. No matter what your starting point is, that's how you'll create the retirement you want.