There's a specific moment that happens in financial planning meetings, and it happens often enough that it has a pattern. Someone in their late 40s or early 50s pulls up their 401(k) balance, sees a number with six figures, and feels a wave of relief. They've been contributing for years, so the number makes them feel comfortable and safe.
Then you run the retirement income calculation, the room gets quiet, and the anxiety slowly builds.
According to Vanguard's How America Saves 2025 report, the average 401(k) balance across nearly 5 million participants hit $148,153 in 2024, up from $134,128 the year before. Contribution rates hit a record high, and people are saving more consistently than at any point in recent memory. Yet a Schroders survey from 2025 found that 87% of non-retired Americans are at least slightly concerned about not knowing how to generate income in retirement, with more than half concerned or very concerned about outliving their assets entirely. That's the dominant financial fear of working America, and it lives in the gap between account balance and actual monthly check.
The Math Nobody's Statement Shows
The 4% rule is the most widely used framework for estimating how much you can safely withdraw from a retirement portfolio each year without running out of money over a 30-year span. It was developed by financial planner William Bengen in 1994, and Morningstar's December 2025 research pegs the optimal withdrawal rate at 3.9% for people retiring in 2026, close enough that the 4% shorthand still works for planning purposes.
A $1 million balance, the number that feels like the finish line for most people, produces about $40,000 a year under that rule. Every retirement blog on the internet can tell you that. Here's what they skip: both of those numbers are gross. Every dollar in a traditional 401(k) carries an embedded tax bill that hasn't come due yet, which means the statement is quietly overstating what you own.
Statement balance | 4% annual | Monthly, pre-tax | At 15% effective tax | At 25% effective tax |
$500,000 | $20,000 | $1,667 | $1,417 | $1,250 |
$800,000 | $32,000 | $2,667 | $2,267 | $2,000 |
$1,000,000 | $40,000 | $3,333 | $2,833 | $2,500 |
The after-tax columns use illustrative flat effective rates. Your actual rate depends on your other income, your state, and your withdrawal strategy.
Look at the spread between the last two columns. On a $1 million account, the difference between retiring at a 15% effective rate and a 25% effective rate is $100,000 over the life of the account, and it isn't luck. It's determined by decisions made in the ten years around retirement: which accounts you draw from first, what you convert to Roth in the low-income years, when you take Social Security, and how you handle required distributions. Two neighbors with identical statements can retire with six figures of difference in after-tax wealth, having earned and saved exactly the same.
None of those figures include Social Security, which matters enormously and varies by individual. The average retired worker's check is about $2,071 a month in 2026, and the program was designed to be a floor, not a complete income replacement. The median 401(k) balance across all Vanguard participants sat at $38,176 in 2024, with the $148,153 average dragged up by the accounts of high earners. Half of all 401(k) participants have less than $38,176 saved.
Why the Balance Feels Like Enough
The brain responds to a large number the same way it responds to a full tank of gas: as abundance rather than a rate. A full tank doesn't tell you how far you can drive or how fast you're burning fuel. The 401(k) balance works the same way. It shows the tank. The rate at which 30 years of retirement will drain it is a separate calculation entirely, and the statement your plan sends every quarter never makes it.
Two things make the conversion problem worse than most people expect.
The first is taxes, and not in the way most people expect. Once Social Security enters the picture, each additional 401(k) dollar you withdraw can pull up to 85 cents of your benefit into taxable income along with it. The result is a marginal rate your tax bracket doesn't admit to.
The bracket you think you're in | What the next 401(k) dollar actually costs |
10% | up to 18.5% |
12% | up to 22.2% |
22% | up to 40.7% |
Each withdrawn dollar can drag up to $0.85 of Social Security into taxable income, so the effective rate is 1.85 times your bracket while benefit taxation phases in. Once 85% of your benefit is fully taxable, the rate falls back to your bracket.
Advisors call it the tax torpedo, and your plan statement has no field for it. Stack required minimum distributions on top, which start at 73 (75 if you were born in 1960 or later) whether you need the income or not, and the tax picture of your 70s is largely decided by what you did in your 60s.
The second is sequence-of-returns risk. If the market drops 30% in your first two years of retirement and you're pulling money out at the same time, you're selling shares at depressed prices and leaving fewer shares to recover when the market bounces. The related mistake is fleeing to cash after the drop. Fidelity examined the 2022 to 2025 market cycle and found that a saver who started with $100,000, stayed invested, and kept contributing ended the period with $191,463, while one who moved out of stocks ended with $105,586. That's an $86,000 gap for someone still adding money. A retiree makes the same flight decision with no contributions left to soften it, at exactly the moment withdrawals are locking in the damage. (Historical illustration from Fidelity's data; past markets don't predict future ones.)
The Number To Build Toward
Working backwards from income is a more useful frame than watching a balance grow. Take the annual income you'll need from your portfolio, after Social Security and any other sources, and multiply by 25. That's your target balance under the 4% rule. Then remember the target is a gross number: if most of it will sit in traditional accounts, the real target is higher, because the IRS owns a slice of every dollar in them.
If you need $60,000 a year from your savings, you need $1.5 million. If you need $80,000 a year, you need $2 million. A Bankrate survey from 2025 found that the median retirement savings target Americans think they'll need is $875,000. The median actual balance for people approaching retirement is a fraction of that, and the gap between expectation and reality is where most retirement shortfalls quietly accumulate.
The discomfort of running these numbers is the point. That math is much more actionable at 42 than it is at 59.
Where To Start
Four things move the needle here, and none of them require a financial advisor to do first.
Multiply your current balance by 0.04 and divide by 12. That monthly figure, before taxes, is what your savings generate today in retirement income. If the number surprises you, you now know the size of the gap while you still have runway to close it.
Pull your Social Security estimate at ssa.gov. It takes about four minutes and shows your projected monthly benefit at different claiming ages. Combined with your portfolio withdrawal, that's your full retirement income picture. Most people have never seen it.
Understand the difference between your pre-tax and post-tax balances. A $300,000 Roth 401(k) and a $300,000 traditional 401(k) are not the same figure. The Roth comes out tax-free in retirement. The traditional gets taxed as ordinary income on the way out, and the mix of both gives you flexibility that an entirely traditional account doesn't.
Revisit the income math at least once a year rather than watching the balance and assuming the trajectory is fine. The balance growing feels like progress. The income number tells you whether the progress is enough.