It is the bluntest question in personal finance: if I start spending this pot, when does it hit zero? This calculator answers it to the month. Enter your starting pot, the monthly amount you withdraw, the return your money keeps earning, and inflation — because a €1,500 withdrawal today must become €1,530 next year to buy the same groceries. The simulation runs month by month for up to 100 years and tells you the exact year and month the money runs out, or that it never does.
By Kestutis Balciunas · Last reviewed: 17 July 2026 · Figures and rules are 2026-vintage estimates — verify current data before acting. Educational tool, not advice.
How the simulation works
Each month the pot earns one month of return, then pays out your withdrawal: pot = pot × (1 + r/12) − withdrawal. At the end of every year the withdrawal itself rises with inflation, so your standard of living stays constant in real terms. The clock stops the first month the pot cannot cover the withdrawal. A worked example: €100,000, withdrawing €2,000/month with no return and no inflation, lasts exactly 50 months — 4 years and 2 months. Add a 5% return and the interest earned each month pushes depletion years further out; add inflation and the growing withdrawals pull it closer again. The tug-of-war between those two forces is the whole answer.
The perpetuity condition — when money lasts forever
There is a tipping point. If your first-year withdrawal rate (12 × monthly withdrawal ÷ pot) stays at or below your real return — (1 + return) ÷ (1 + inflation) − 1 — the pot’s growth covers every inflation-adjusted withdrawal indefinitely and the simulation survives all 100 years. The tool shows this check explicitly. A €200,000 pot paying €1,000/month at a 6% return with zero inflation sits exactly on the knife edge: the pot earns €1,000/month and pays €1,000/month, forever. One notch more withdrawal and depletion begins; this is precisely the logic behind safe withdrawal rates, which you can explore properly in the safe withdrawal rate calculator.
Reading the depletion timeline
The bars show your remaining pot at 5, 10, 20 and 30 years. A pot on a sustainable path holds its height or grows; a depleting pot visibly melts, and the melt accelerates — the less capital remains, the less it earns, the faster withdrawals bite. That acceleration is why “it still looks fine after ten years” is a dangerous signal, and why the classic 4% studies matter for Europeans too: we unpack them in the European 4% rule and the more flexible approaches in alternatives to the 4% rule.
What the model deliberately ignores
The simulation assumes a smooth, constant return — real markets do not cooperate. A crash in the first five years of withdrawals (sequence-of-returns risk) shortens the real answer versus this model’s, which is why retirement researchers recommend withdrawal rates well below the perpetuity threshold. Taxes and fund fees are also not modelled — verify current rates for your country. Use the result as a planning estimate, not a guarantee, and if the answer worries you, work the problem from the other end: the financial freedom calculator shows the pot size that makes your target income sustainable, and the European pension gap calculator shows how much of that load your state pension already carries.
A practical way to use the tool: run your honest numbers once, then stress-test. Drop the return by two points, raise inflation by one, and see whether the answer still outlives you. If a modest pessimism flips “forever” into “24 years”, your plan is leaning on optimistic assumptions rather than on capital — better to learn that from a slider today than from a bank statement at 78. All estimates, not financial advice.
These numbers make more sense with the guide
The free 12-page Starter Kit turns them into decisions: your first fund, a safe broker, and the tax basics for your country.
Frequently asked questions
Q: Why does my withdrawal amount increase every year in the simulation?
A: Because keeping your lifestyle constant is the realistic assumption. A fixed €1,500/month buys noticeably less after a decade of even 2% inflation, so the tool raises the withdrawal by your inflation rate every year. Set inflation to 0 if you genuinely want a fixed nominal withdrawal.
Q: What does ‘lasts forever at these settings’ actually mean?
A: It means your pot survived the full 100-year simulation, which happens when your withdrawal rate is at or below your real (after-inflation) return. It is a mathematical statement about constant returns, not a promise — volatile real-world returns can break a portfolio that looks perpetual on paper.
Q: What is sequence-of-returns risk and why isn’t it in the model?
A: It is the danger of hitting poor market years early in retirement, when withdrawals lock in losses that a later recovery cannot fully repair. A simple simulator uses one smooth return so results stay transparent and reproducible; treat its answer as optimistic by a margin, and choose withdrawal rates conservatively.
Q: Should I enter my return before or after inflation?
A: Enter the nominal return (before inflation) and your expected inflation separately — the tool handles the interaction, growing your withdrawals while your pot compounds. Entering a real return and 0% inflation gives nearly the same answer and is a fine sanity check.
Q: How is this different from a safe withdrawal rate calculator?
A: This tool answers ‘how long until zero?’ for a spending plan you choose; an SWR tool answers ‘what spending level is safe more or less indefinitely?’. They are two views of the same math — if this calculator says your money runs out at year 22 of a 35-year retirement, the SWR view tells you what withdrawal would have survived.