Retirement Withdrawal Calculator — the 4% rule, year by year

The retirement withdrawal calculator above simulates your portfolio year by year, applying an inflation-adjusted withdrawal each year and growing whatever's left at your expected rate of return. It's built specifically around the classic "4% rule" style of retirement drawdown, where you take out a set percentage in year one and then raise that dollar amount every year to keep pace with inflation.

Arb Digital built this tool because the 4% rule gets repeated constantly in retirement articles, but almost nobody actually shows the year-by-year math — and that math is where the real risk hides. Run your own numbers here before you assume any withdrawal rate is safe for your specific retirement.

What This Calculator Does

Starting from your portfolio value at retirement, this tool withdraws your chosen percentage in year one, then increases that withdrawal amount by your inflation rate every subsequent year — the hallmark of the classic 4% rule approach. After each withdrawal, it grows the remaining balance at your expected annual return, then repeats the process for every year you specify.

The result shows you not just a single number, but the full trajectory: what your income looks like in year one, what it looks like by year 30 after decades of inflation adjustments, what's left in the portfolio at the end of the period, and — critically — whether the money runs out before your retirement horizon is over, and if so, in which year.

How to Use It

1. Enter your portfolio value at retirement. This is your total investable savings — 401(k), IRA, brokerage, and similar accounts — on the day you plan to start withdrawing.
2. Set your initial withdrawal rate. The classic figure is 4%, but you can test 3%, 5%, or any rate you're considering.
3. Enter your expected annual return and inflation rate. These drive both portfolio growth and how quickly your withdrawal amount rises each year.
4. Choose your retirement horizon. 30 years is a common planning assumption for someone retiring in their mid-60s, but adjust it for your own expected timeline.
5. Read the results. The big number is your first-year withdrawal; the grid shows monthly income, your final year's inflation-adjusted withdrawal, ending balance, and — if the plan fails — the exact year it runs dry.

The Formula / How It's Calculated

In year one, the withdrawal equals your portfolio value multiplied by your chosen withdrawal rate. In every following year, that dollar withdrawal grows by your inflation rate — so your purchasing power stays roughly constant even as the dollar figure rises. Each year, after subtracting the withdrawal, the remaining balance is grown by your expected annual return before the next year's withdrawal is taken.

This sequential, year-by-year simulation is exactly how the original 4% rule research worked. The rule traces back to financial planner William Bengen's research in the 1990s and was later reinforced by the Trinity Study, an academic analysis of historical market returns. You can read a plain-language overview of the underlying research and its assumptions at Investopedia.

The 4% Rule Is a Historical Guideline, Not a Promise

It's worth being precise about what the 4% rule actually claims. Bengen's original research, and the later Trinity Study, looked backward at historical U.S. market returns and asked: what withdrawal rate would have survived the worst 30-year stretches in that historical dataset? The answer, roughly, was 4%. That's a statement about the past, applied as a guideline for the future — it is not a mathematical guarantee, and future markets don't have to resemble historical ones.

That distinction matters enormously in practice. A withdrawal rate that "worked" across most 30-year historical periods still failed in some of them — and nobody knows in advance which kind of 30-year period they're about to live through.

Sequence-of-Returns Risk: Why the First Five Years Matter Most

The single biggest danger hiding inside any fixed-percentage withdrawal strategy is sequence-of-returns risk: the fact that the order in which you experience good and bad market years matters enormously, even if the average return over the full period is identical. A retiree who hits a severe market downturn in years one through five of retirement — while still withdrawing a fixed, inflation-adjusted amount — can permanently damage their portfolio's ability to recover, even if the market fully rebounds afterward.

Compare that to a retiree who experiences the exact same average return but in reverse order — strong years first, weak years later. That retiree's portfolio, cushioned by early growth, often survives the same average return path comfortably. Same average, wildly different outcome. This is precisely why two portfolios with identical average returns over 30 years can produce completely different survival results depending purely on when the bad years happened to land.

Guardrail Strategies: Why Flexibility Beats Precision

Because a fixed, inflation-linked withdrawal ignores what the market is actually doing in real time, many retirement researchers now recommend "guardrail" strategies instead: rules that adjust your withdrawal up or down based on how your portfolio is actually performing. A common approach cuts your withdrawal (skip the inflation raise, or take an outright reduction) after a bad market year, and allows a modest increase after a strong one.

The core insight behind guardrails is simple: a retirement plan built entirely on rigid precision — "I will withdraw exactly 4%, adjusted for inflation, no matter what" — is more fragile than one built on flexibility. Retirees who can tolerate cutting discretionary spending in a down year dramatically improve the odds that their money lasts as long as they do, compared to retirees locked into a fixed schedule regardless of market conditions.

Why Your Time Horizon Should Change Your Withdrawal Rate

The original 4% figure was built around a roughly 30-year retirement horizon. Someone retiring earlier — say, in their 50s, pursuing an early-retirement or FIRE-style plan — is asking their portfolio to survive 40 years or more, which historically has required a noticeably lower starting withdrawal rate to achieve similarly high survival odds. Conversely, someone retiring later, in their mid-70s, with a shorter expected time horizon, can often sustain a meaningfully higher withdrawal rate without materially increasing their risk of running out of money.

This is one of the most useful things to test directly in the calculator above: run the same portfolio and return assumptions at a 25-year horizon and again at a 35-year horizon, and watch how much the ending balance and depletion risk shift. There is no single "correct" withdrawal rate — there's only the rate that's appropriate for your specific time horizon, spending flexibility, and other income sources.

Asset Allocation Quietly Drives This Entire Calculation

The "expected annual return" you enter into this calculator isn't a fixed law of nature — it's a direct reflection of how your portfolio is allocated between stocks, bonds, and cash. A more stock-heavy portfolio has historically produced higher average returns, which supports a higher sustainable withdrawal rate over long horizons, but it also comes with more volatility, which is precisely the ingredient that makes sequence-of-returns risk dangerous in the first place. A more conservative, bond-heavy portfolio smooths out that volatility but typically lowers the long-run average return your withdrawals depend on.

Many retirees address this tension with a strategy sometimes called a "bond tent" or a rising equity glide path — holding more in bonds and cash right around the retirement transition, when sequence-of-returns risk is highest, and gradually shifting back toward stocks in later retirement years once that early danger zone has passed. Whatever allocation you choose, it's worth remembering that the return assumption you plug into any withdrawal calculator, including this one, is a direct consequence of that underlying asset mix, not an independent variable.

Common Mistakes to Avoid

• Treating 4% as a universal, risk-free number. Your ideal rate depends on your specific time horizon, asset allocation, and tolerance for adjusting spending.
• Ignoring sequence-of-returns risk. The order of returns matters as much as the average return itself, especially in the first decade of retirement.
• Assuming a single average return every year. Real markets are volatile; a smooth 6% every year is a simplification, not a forecast.
• Refusing to ever adjust spending. Rigid adherence to a fixed inflation-adjusted withdrawal, regardless of market performance, increases the risk of running out of money.
• Forgetting taxes and required minimum distributions. Withdrawals from tax-deferred accounts are usually taxable income and may be subject to RMD rules later in retirement.

Related Free Tools From Arb Digital

This calculator works best alongside a full retirement-income picture. Try our Social Security Benefits Calculator and Pension Calculator to estimate guaranteed income sources, the RMD Calculator for required minimum distribution planning, and the FI Number Calculator to check your target nest egg before you retire. Explore every calculator in our free online tools hub.

Frequently Asked Questions

This tool provides general estimates for educational purposes only and is not financial, tax, legal, or medical advice. Figures are illustrative; consult a licensed professional for decisions.