Retirement & Safe Withdrawal Rate (FIRE) Calculator
Determine your exact Financial Independence Number, analyze Trinity Study safe withdrawal rates (3.0% - 4.5%), and evaluate portfolio longevity.
Parameters & Lifestyle Targets
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Asset Trajectory Simulation
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Decade-by-Decade Cashflow Ledger
Synthesizing investment returns, inflation-adjusted withdrawals, and sustainable spending capacity.
| Milestone Age | Portfolio Beginning Value | Annual Inflow / Savings | Withdrawal (Inflation-Adj.) | Investment Growth | Ending Balance |
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The Mathematical Mechanics & Bengen Rule
First formalized in William Bengen's 1994 paper and extended by Trinity University researchers (Cooley, Hubbard, and Walz) in 1998, the Safe Withdrawal Rate is the share of a diversified stock/bond portfolio a retiree withdraws in year one, then raises each year only for inflation. A 4% rate survived every historical 30-year period in Bengen's US data — a strong track record, not a guarantee.
Sequence of Returns Risk (SORR)
The largest vulnerability in early financial independence is experiencing a sharp bear market in the first 3-5 years of retirement. When portfolio value declines while withdrawals continue, the losses become permanent.
Skipping the inflation raise after losing years, and trimming spending when the withdrawal rate drifts too high, lets a higher starting rate survive historical downturns.
Holding 24-36 months of baseline living costs in cash or short-duration bonds avoids selling depressed equities early in retirement.
How this calculator works
While you are working, your invested net worth grows each month at the pre-retirement return and your annual savings are added in monthly installments. From your target retirement age, savings stop and you withdraw your desired spending, raised every year by inflation, while the rest of the portfolio earns the post-retirement return. The projection runs to age 95.
Your FIRE number is your annual spending divided by the safe withdrawal rate, in today's dollars. The FIRE projection shows the first month your portfolio — if you kept saving — would reach that number after adjusting for inflation. Coast FIRE is the amount you'd need invested today to reach your FIRE number by your target age with no further savings.
Sequence of returns risk, explained
Two retirees with the same average return can end up with very different outcomes depending on the order of those returns. Losses early in retirement hurt most, because withdrawals lock in the lower prices and leave less capital to recover. That is why the safe withdrawal rate is built around the worst historical starting years rather than the average — and why this calculator's smooth, average-return projection should be read as a central estimate, not a worst case.
- Lower your starting rate. 3.25–3.5% gives more room for a bad first decade, especially for retirements longer than 30 years.
- Stay flexible. Guardrail rules that cut spending modestly after poor years have historically let retirees start higher and still finish safely.
- Hold a buffer. A couple of years of spending in cash or short-term bonds means you rarely have to sell stocks after a crash.
Where Social Security fits in
This calculator projects your own investments only — it doesn't include Social Security. Full retirement age is 67 for anyone born in 1960 or later; you can claim as early as 62 at a reduced amount, or delay up to 70 for an increased amount. Subtract your expected annual benefit from your spending before entering it here, and your FIRE number drops accordingly.
Read the guide: How much money do you need to retire? The 25x rule explained
Frequently asked questions
What is the 4% withdrawal rule?
A guideline from William Bengen's 1994 research: withdraw 4% of your portfolio in the first year of retirement, then increase that dollar amount with inflation each year. Historically this lasted at least 30 years for a balanced US stock and bond portfolio. It implies a savings target of about 25× your annual spending.
How much do I need to retire?
Divide your expected annual spending by your safe withdrawal rate: $60,000 a year at 4% needs $1.5 million, at 3.5% about $1.71 million. Subtract any Social Security or pension income from spending first.
What is Coast FIRE?
Coast FIRE is the point where your existing investments, left to grow with no new contributions, will reach your full FIRE number by your target retirement age. After that you only need to earn enough to cover current expenses.
Does this account for inflation?
Yes. Retirement withdrawals rise with your inflation rate every year, the FIRE projection compares your portfolio to an inflation-adjusted target, and the chart shows balances in today's dollars.
What return rate should I assume?
Long-run US stock returns have averaged roughly 10% a year before inflation, and a balanced portfolio less. Many planners use 6–8% while saving and 4–6% in retirement, when portfolios usually hold more bonds. Returns vary widely from year to year and are not guaranteed.
How does Social Security change how much I need saved?
Social Security covers part of most retirees' expenses, so subtract your expected annual benefit from your target spending before applying the withdrawal rate — you likely need less saved than a benefit-blind calculation suggests.
Methodology based on Bengen (1994) and Cooley, Hubbard & Walz (1998) · Our methodology · Last updated September 2026