Mini test 010 / FIRE income / Withdrawal duration
Can $4 million pay $13,000 a month forever?
A post seen more than 84,000 times says $4 million growing at 7% can pay roughly $13,000 a month forever without hurting the investment. The first-year arithmetic works. The two promises do not.
The monthly arithmetic is right. The forever promise is not.
Four percent of $4 million is $160,000 a year, or $13,333 a month. But the usual 4% rule asks whether inflation-adjusted spending lasted through a chosen period. It does not guarantee an endless payment or an untouched $4 million balance.
01 / Check the arithmetic
The $13,000 figure is a rounded first-year amount.
The exact first-year calculation is $4 million × 4% = $160,000. Divide that by twelve and the monthly amount is $13,333 before tax. Calling it $13,000 is reasonable rounding.
If the portfolio grew by exactly 7% in one smooth year, gross growth would be $280,000. Subtracting the $160,000 withdrawal leaves $120,000 before inflation, taxes, costs and any variation in returns. That is a hypothetical year, not what an index fund pays like a salary.
The first withdrawal works on a calculator. That does not settle how long the plan lasts.
02 / Three different spending rules
“Take 4%” can describe three plans with different outcomes.
| Rule | What changes | What it can promise |
|---|---|---|
| $13,333 every month | The dollar payment stays flat | Future purchasing power falls |
| 4% of the current balance | Spending falls when the portfolio falls | No fixed monthly income |
| The usual 4% rule | The first $160,000 rises with inflation | Survival only over the tested period |
In a hypothetical world with 3% inflation, a fixed $13,333 monthly payment thirty years from now would buy what about $5,493 buys today. That does not mean 3% inflation will occur. It shows why a flat dollar payment and an inflation-adjusted retirement income are not the same promise.
Decide whether income may fall, whether it must keep up with inflation and how long it must last before choosing a withdrawal rule.
03 / What a real successful path did
Thirty years is not forever—and success did not preserve principal.
A published implementation of the 4% rule followed a 50% stock, 50% bond portfolio from January 1950 through December 1979. It took 4% initially, increased spending with inflation and did not run out during those thirty years.
The ending real balance was 95.2% of the starting balance. Scaled to $4 million, that is $3,808,000—about $192,000 less purchasing power than the retiree started with. The plan passed the survival test while missing the untouched-principal promise.
A successful thirty-year withdrawal does not prove the same payment lasts forever or leaves the starting wealth intact.
04 / Use the result
Test lifetime spending and the ending balance as separate goals.
If $13,333 of real monthly spending must continue for life, use the actual horizon, portfolio, taxes, fees and other income. If leaving $4 million of purchasing power also matters, add that as a separate ending-balance requirement.
The free FIRE planner can compare the spending you want with three portfolio approaches. For the underlying rule, see why the 4% rule does not promise to preserve principal.
$4 million supports a $160,000 first withdrawal under the rule. “Forever” and “without hurting the investment” need stronger tests.
The full receipt
What exactly did we check?
The source claim
The claim came from this X post. It had 84,439 views, 611 likes, 54 replies, 28 reposts and 105 bookmarks when checked. We tested its $4 million, 7%, 4%, $13,000 monthly, forever and principal-preservation statements separately.
The withdrawal evidence
William Bengen's original 1994 research tested inflation-adjusted withdrawals over finite historical retirements. The Financial Planning Association's published 1950–1979 example reports the 0.952 real ending factor used here.
Calculation and limits
The first withdrawal, monthly amount and smooth 7% year are direct arithmetic. The 3% inflation example is explicitly hypothetical. The historical $4 million ending value simply scales the source's published real growth factor; we did not re-create its portfolio from raw monthly data.
We did not forecast index-fund returns or choose a withdrawal rate for an individual. Taxes, fees, account type, other income and personal spending are outside this narrow check. Historical success does not guarantee future results. This is educational research, not personal financial advice.
Use this result
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Enter what you have and what you want to spend each month. Compare three portfolios against the same market history. Your financial figures stay in your browser.
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