Think $600K isn’t enough to retire? Here’s how your nest egg could actually keep growing after you stop working

Vishesh Raisinghani

Thu, August 27, 2026 at 3:30 PM GMT+3 11 min read

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Most Americans believe they need to be millionaires to retire comfortably. As of 2025, the "magic number" for retirement was $1.46 million, according to Northwestern Mutual's 2026 Planning & Progress Study, up $200,000 from 1.26 million in 2025. Nearly half (48%) also worry they could outlive their savings (1).

So what if you're approaching retirement with less than half that "magic number" — say, $600,000?

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It doesn't necessarily mean you'll spend retirement watching your savings steadily disappear. Depending on how much income you receive from Social Security and other sources, how much you withdraw and how your investments perform, a portfolio can continue generating returns even after you stop contributing to it.

Under the right conditions, someone who retires with $600,000 could even finish retirement with considerably more than they started with. But that outcome is far from guaranteed: market volatility, inflation, taxes, unexpected expenses and the timing of investment losses can all affect how long a portfolio lasts.

Here are three factors that can determine whether your savings shrink — or potentially continue growing — after you retire.

1. How much you actually spend

Retirement doesn't necessarily mean years of free spending and expensive hobbies. In fact, research suggests many retirees are surprisingly reluctant to spend their savings.

Research published in 2025 by David Blanchett and Michael Finke in Financial Planning Review revealed that 65-year-old couples holding retirement assets of $100,000 or more draw down only 2.1% annually (2). For unmarried retirees in the same category, the withdrawal rate is even lower at approximately 1.9%.

That's significantly lower than the so-called 4% rule that many financial planners use as a starting point for retirement withdrawal strategies (3).

Some expenses can also disappear or decline once you leave work. You may no longer have commuting costs, work attire or daily office meals, for example. Once you turn 65, Medicare can also cover a portion of your health care costs.

Other expenses can rise, however, and housing, medical care and long-term care can consume a significant share of a retiree's budget. That's why the amount you expect to spend matters much more than any national rule of thumb.

And without a paycheck coming in every two weeks, keeping tabs on those expenses — and how much you're pulling from your portfolio to cover them — becomes especially important.

Get help making your retirement savings last

Figuring out how much you can afford to spend in retirement isn't always as simple as following a rule of thumb. Your savings, Social Security income, investments, taxes and expected expenses can all affect how much you can comfortably withdraw each year.

A financial advisor can help crunch those numbers and build a retirement plan around your individual circumstances.

But hiring an advisor can be a lifelong commitment, which might make or break your retirement. That's why finding a reliable advisor is crucial.

That's where Advisor.com can come in. The platform connects you with an expert near you for free.

Advisor.com does the heavy lifting for you, vetting advisors based on track record, client ratios and regulatory background. Plus, its network comprises fiduciaries, who are legally required to act in your best interests.

Just enter a few details about your finances and goals, and Advisor.com's AI-powered matching tool will connect you with a qualified expert best suited to your needs based on your unique financial goals and preferences.

Finding the right advisor isn't always easy — there's no one-size-fits-all solution. That's why Advisor.com lets you set up a free initial consultation, with no obligation to hire, to see if they're the right fit for you.

2. How much guaranteed income you have

One reason some retirees can leave more of their investments untouched is that their savings aren't their only source of income.

Social Security is the most obvious example. As of July 2026, the average retired worker receives about $2,086 per month, according to the Social Security Administration (5).

The Social Security trustees' 2026 report projects that the Old-Age and Survivors Insurance Trust Fund, which pays retirement and survivor benefits, will be able to pay 100% of scheduled benefits until the fourth quarter of 2032. If Congress makes no changes before its reserves are depleted, continuing program income would still be sufficient to cover about 78% of scheduled benefits at that point (6).

For today's retirees, those monthly benefits can significantly reduce the amount they need to withdraw from investments.

The SSA estimates that an aged couple in which both spouses receive benefits gets an average of about $3,208 per month, or $38,496 per year, in 2026 (7).

Consider a retired couple with $600,000 in savings and $60,000 in annual expenses. If they received $38,496 from Social Security, they'd have a gap of about $21,500 to cover from their portfolio.

That's equivalent to withdrawing roughly 3.6% of a $600,000 portfolio in the first year.

Of course, that's only an illustration. Social Security benefits vary widely based on earnings history and claiming age, while expenses and portfolio values change over time. But it shows why the size of your nest egg alone doesn't tell you whether you're prepared for retirement.

Keep your retirement cash within reach — and growing

It also matters where you keep the money you expect to spend. While longer-term savings can remain invested for potential growth, retirees may want to keep money needed for upcoming expenses somewhere more accessible.

But keeping that money within easy reach doesn't necessarily mean settling for little or no return.

A high-yield account like a Wealthfront Cash Account can be a great place to grow your uninvested cash, offering both competitive interest rates and easy access to your money when you need it.

A Wealthfront Cash Account currently offers a base APY of 3.30% through program banks, and new clients can get an extra 0.75% boost during their first three months on up to $150,000 for a total variable APY of 4.05%.

That's 10 times the national deposit savings rate, according to the FDIC's July report.

Additionally, Wealthfront is offering new clients who enable direct deposit ($1,000/mo minimum) to their Cash Account and open and fund a new investment account an additional 0.25% APY increase with no expiration date or balance limit, meaning your APY could be as high as 4.30%.

With no minimum balances or account fees, as well as 24/7 withdrawals and free domestic wire transfers, your funds remain accessible at all times. Plus, you get access to up to $8M FDIC Insurance eligibility through program banks.

3. What happens to the money you don't spend

Retiring doesn't mean you have to stop investing.

That's an important part of the math behind retirement withdrawals: while you're taking some money out, the portion that remains invested still has the opportunity to generate returns.

The traditional 4% rule was developed by financial planner William Bengen in the 1990s using historical market returns to estimate how much retirees could initially withdraw while making their money last for roughly 30 years.

More recent research shows why the appropriate number isn't set in stone. Morningstar's latest retirement-income research estimates a 3.9% starting withdrawal rate for retirees seeking consistent inflation-adjusted spending over 30 years with a 90% probability of having money remaining at the end. More flexible spending strategies could support higher starting withdrawals under its analysis (8).

The key point isn't that 3.9%, 4% or any other percentage guarantees success. It's that retirees generally don't put their entire nest egg in cash and then subtract their living expenses from it until nothing remains.

A diversified portfolio may continue appreciating while withdrawals are taking place. During strong market periods, investment gains can exceed the amount being withdrawn, allowing the balance to grow. During downturns, however, the opposite can happen.

That latter risk is particularly important early in retirement. Selling investments after a major market decline can leave less money invested to participate in an eventual recovery — one reason retirees shouldn't assume historical average returns will arrive smoothly every year.

Build your nest egg in small steps

So, if you're looking to keep making small investments to add to your retirement savings, you might want to consider using platforms like Acorns, which gives you a simple and automatic way to turn your spare change from everyday purchases into an investment opportunity.

It works like this: Once you link all your cards, Acorns will automatically round up all expenses to the nearest dollar and invest the difference into a diversified portfolio of ETFs managed by experts at leading investment firms like Vanguard and BlackRock.

For instance, when you buy your morning coffee for $4.25, Acorns deducts $5 from your account and invests the difference, making that purchase a 75-cent investment into your future.

If you sign up today with a monthly contribution, you can get a $20 bonus investment.

How $600,000 could grow to nearly $1.5 million

So what could this actually look like over a long retirement?

Consider a retired couple with $600,000 invested in a traditional 60/40 portfolio, with 60% in stocks and 40% in bonds. Assume the stock portion earns an average annual return of 10%, while the bond portion earns 4%.

That would give the portfolio an average annual return of 7.6%:

60% × 10% = 6.0% (stocks)
40% × 4% = 1.6% (bonds)
Total = 7.6%

Now assume the couple withdraws the equivalent of 4% of their portfolio annually. In a simplified scenario, investment growth exceeding those withdrawals leaves money in the portfolio that can continue compounding.

If the portfolio effectively grew by 3.6% annually after withdrawals, $600,000 would grow to roughly $1.45 million after 25 years.

Real-world returns won't arrive at a steady 7.6% every year, of course. Some years could produce significant gains, while others could bring losses. Withdrawals can also change as expenses and inflation rise.

But the example illustrates an important feature of retirement investing: withdrawing money doesn't necessarily mean your portfolio has to shrink.

If Social Security or other income covers a significant portion of your expenses, you may be able to keep withdrawals relatively modest while leaving the rest of your money invested. Over a retirement that lasts 20, 25 or even 30 years, that leaves plenty of time for compounding to continue working in your favor.

Finding the right mix of investments

But reaching those kinds of returns often comes down to picking the right mix of stocks and bonds — something many investors find challenging. That's where platforms like Moby can help.

Moby provides expert research and recommendations to help you identify strong, long-term investments backed by advice from former hedge fund analysts.

In four years, and across almost 400 stock picks, their recommendations have beaten the S&P 500 by almost 12% on average. They also offer a 30-day money-back guarantee so you can make sure their stock picks align with your appetite for risk.

Moby's team spends hundreds of hours sifting through financial news and data to provide you with market reports delivered straight to you. Their research keeps you up-to-the-minute on stock shifts and can help you reduce the guesswork behind choosing stocks and ETFs.

Plus, their reports are easy to understand for beginners, so you can become a smarter investor in just five minutes.