How Long Until Millionaire?
Estimate years until a target balance.
About the How Long Until Millionaire?
The honest version of the question. How long a million takes depends far more on how much you add each month than on the rate you chase.
How to use it
- Enter what you have saved now.
- Enter your monthly contribution.
- Enter the annual return you expect.
The formula
Here the unknown is time. You know the target, the starting balance, the monthly contribution and the rate; what you want is n. Rearranging the future value formula gives it directly.
n = ln[(FV × r + PMT) ÷ (P × r + PMT)] ÷ ln(1 + r)
Where FV is $1,000,000, P is what you have now, PMT is the monthly contribution and r is the monthly rate. The logarithms are there because you are asking how many times a quantity must multiply to reach a target — which is exactly what a logarithm answers.
The practical consequence of the log is that time responds sluggishly to the rate and sharply to the contribution. Doubling what you save cuts eight years off the journey. Chasing three extra points of return cuts five — and comes with a real chance of adding years instead.
Worked examples
| Starting | Monthly | Return | Years to $1,000,000 |
|---|---|---|---|
| $0 | $500 | 7% | 36.4 |
| $0 | $1,000 | 7% | 27.6 |
| $0 | $2,000 | 7% | 19.6 |
| $0 | $1,000 | 10% | 22.5 |
| $50,000 | $1,000 | 7% | 23.9 |
Rows two and four are the argument this page exists to make. Going from a 7% return to a 10% one saves 5.1 years — and requires you to reliably beat the market, which almost nobody does. Doubling the monthly contribution saves 8.0 years and requires only that you do it. One of those is under your control. Row five is the other lesson: a $50,000 head start is worth 3.7 years, which is why money invested in your twenties is doing work that money invested in your forties cannot.
Common mistakes
- Assuming a million is the finish line. At 3% inflation, a million dollars in thirty years buys roughly what $412,000 does today. The number is a milestone, not a retirement plan, and it should be checked against what you actually intend to spend.
- Planning around an optimistic return. Entering 12% because a good decade happened produces a comfortable answer and a bad plan. Long-run diversified returns after inflation are usually assumed nearer 6% to 7%.
- Forgetting that contributions usually rise. This holds the monthly amount constant for the entire period. Most people's incomes grow, and raising contributions with pay is the single most effective accelerator available.
- Ignoring where the account sits. A million in a taxable account is not a million in a Roth. Tax treatment can move the real answer by years, and it is invisible in the raw arithmetic.
Terms explained
- Compound annual growth rate
- The smoothed annual rate that turns your starting balance into the ending one. Real returns are lumpy; this is their average.
- Contribution
- What you add each month. The variable you control, and the one that dominates early years.
- Real vs nominal
- Nominal ignores inflation, real subtracts it. A million nominal in 2056 is a considerably smaller sum in today's terms.
- Sequence of returns
- The order in which good and bad years arrive. It barely matters while you are accumulating and matters enormously once you start withdrawing.
- Time horizon
- How long the money compounds. The most powerful input, and the only one that cannot be increased later.
- Safe withdrawal rate
- How much of a portfolio can be drawn annually without exhausting it, historically discussed around 4%. On a million, that is $40,000 a year.
Common questions
- Is a million still a lot of money?
- Less than it was. At 3% inflation, a million in thirty years has the buying power of about $412,000 today. At a 4% withdrawal rate it produces roughly $40,000 a year before tax.
- What matters more, saving more or earning a higher return?
- Saving more, and by a wide margin, because it is the input you control. Doubling the contribution from $1,000 to $2,000 saves eight years; a return three points higher saves five and cannot be relied upon.
- What return should I assume?
- A diversified portfolio has historically returned roughly 7% after inflation over long periods, with wide variation. Using 6% to 7% is common; using 12% is planning for the best case and calling it the expected one.
- Does starting early really matter that much?
- Yes. A $50,000 head start at 7% with $1,000 a month reaches the target 3.7 years sooner. The early money compounds for the entire journey, so it does disproportionate work.
- Should I count my house?
- Net worth includes it; an income-producing portfolio does not. A house you live in does not pay you anything, so for retirement purposes the investable total is the more useful number.
- What if I cannot contribute every month?
- The projection assumes you can. Missed months push the date out, though far less than stopping altogether — the balance you have already built keeps compounding whether you add to it or not.
- Does this include employer contributions?
- Only if you include them in the monthly figure, and you should. A match is part of what goes into the account, and leaving it out of the calculation understates your progress.
- How does inflation change the target?
- If you want a million in today's buying power, either raise the target or use a real return — your nominal return minus inflation. Using a real rate answers the question in money you can actually spend.