Wondering how long my retirement money will last is one of the most common — and most stressful — financial questions people face.
Here's a sobering starting point: according to the Society of Actuaries, a healthy 65-year-old couple has a significant chance that at least one spouse will live into their 90s, meaning retirement savings may need to cover 25 to 30 years or more.
The problem is that most people don't know their own number — they save for decades but never calculate whether their withdrawals are sustainable. This article walks you through five essential facts: how to calculate your runway, the 4% rule, how withdrawal rates affect longevity, the role of Social Security, and the tools that make all of this easier.
By the end, you'll be able to estimate your own answer with confidence.
How to Calculate How Long Your Retirement Money Will Last
Figuring out how long my retirement money will last comes down to three variables: your total savings, your annual withdrawal, and your portfolio's growth rate. Divide your nest egg by what you plan to spend each year and you get a rough baseline — then adjust for investment returns and inflation.
The Basic Math
Take a $500,000 portfolio. If you withdraw $40,000 per year with no growth, the money lasts 12.5 years. If the portfolio earns an average 5% annually after inflation while you withdraw 6%, it shrinks each year and runs out faster. That's why withdrawals matter more than the starting balance when projecting how long my retirement money will last.
Use Real Numbers, Not Guesses
The U.S. Bureau of Labor Statistics reports that households headed by people age 65 and older spend an average of roughly $60,000 per year — a useful benchmark for estimating your own needs. List your expected expenses, subtract guaranteed income like pensions, and the gap is what your savings must cover.
How to apply this: Write down your annual expenses, subtract any pensions or annuities, and divide your savings by that gap for your first estimate of how long my retirement money will last.
The 4% Rule: Your Baseline Benchmark
The most famous guideline for estimating how long my retirement money will last is the 4% rule. It comes from the 1994 "Trinity Study" research by William Bengen, which found that withdrawing 4% of your portfolio in year one — then adjusting for inflation annually — historically allowed money to last at least 30 years across most market conditions.
Why 4% Works (and When It Doesn't)
The rule assumes a diversified stock-and-bond portfolio and a 30-year horizon, which is why it remains the default starting point for how long my retirement money will last. It holds up less well if you retire early, face unusually high inflation, or retire into a bear market — a risk researchers call sequence-of-returns risk.
Vanguard's research notes that withdrawal rates closer to 3.3%–3.5% may be more prudent when starting valuations are high.
Quick Reference Comparison
| Withdrawal rate | Estimated duration | Best suited for | Action to take |
|---|---|---|---|
| 3% | 30+ years | Early retirees | Stress-test with a calculator |
| 4% | ~30 years | Age 65 retirees | Rebalance annually |
| 5% | ~20–25 years | Shorter horizons | Build a cash buffer |
| 6%+ | Under 20 years | Needs review | Cut spending or work longer |
How to apply this: Multiply your savings by 4% — if that figure doesn't cover your annual spending gap, your money likely won't last 30 years without adjustments.
Factors That Shorten or Extend Your Runway
How long my retirement money will last depends heavily on variables beyond the withdrawal rate itself. Three factors do most of the damage — or most of the good.
- Inflation: At 3% annual inflation, prices roughly double every 24 years, quietly halving your purchasing power.
- Sequence of returns: Big losses early in retirement force you to sell shares at depressed prices, permanently damaging the portfolio.
- Healthcare costs: Fidelity's annual Retiree Health Care Cost Estimate projects that a single 65-year-old may need well over $100,000 saved just for medical expenses in retirement.
A common scenario: two retirees with identical $750,000 portfolios can end up with dramatically different outcomes purely because one retired in 2000 and the other in 2010. Market timing at the start of retirement matters enormously, and it can swing how long my retirement money will last by a decade or more.
How to apply this: Build a cash reserve covering one to two years of withdrawals so you never sell investments during a downturn.
Tools and Calculators That Give You a Real Answer
Guessing is not a strategy. Several free, reputable tools can model hundreds of market scenarios and give you a probability-based answer about how long my retirement money will last.
- Fidelity Retirement Score: Estimates whether your savings are on track and shows how changes in spending or retirement age shift your outcome.
- Social Security Administration: Lets you create an account and view your actual benefit estimates — essential input for any calculation.
- Vanguard Retirement Nest Egg Calculator: Models withdrawal scenarios using Monte Carlo simulation.
The U.S. Securities and Exchange Commission's Investor.gov also offers a free savings goal calculator and reminds investors that "compound interest" calculators are estimates, not guarantees — always check the assumptions behind any tool you use.
How to apply this: Run your numbers through at least two of these tools this week and compare whether they agree on your retirement timeline.
How to Make Your Money Last Longer
If your calculations show a shortfall, you have more levers than you might think. Each adjustment changes how long my retirement money will last — often dramatically.
- Delay Social Security. Benefits grow roughly 8% per year for each year you delay past full retirement age, up to age 70, per the Social Security Administration.
- Work one to two years longer. This simultaneously adds savings, delays withdrawals, and shortens the horizon your money must cover.
- Cut fixed costs. Downsizing or paying off a mortgage reduces the annual gap permanently.
- Use a dynamic withdrawal strategy. The Vanguard research on "guardrail" strategies shows that flexible withdrawals — spending slightly less after bad market years — can meaningfully extend portfolio life.
Consider a retiree who drops from a 5% to a 4% withdrawal rate on a $600,000 portfolio: that single change reduces annual withdrawals by $6,000 but can extend how long my retirement money will last by a decade or more.
How to apply this: Pick one lever — delaying benefits, trimming spending, or adding a flexible withdrawal rule — and model its impact in a calculator before committing.
Frequently Asked Questions About how long my retirement money will last
How does retiring at 55 change how long my retirement money will last?
Retiring 10 years early stretches your money across more years and delays Medicare eligibility until 65, so you must self-fund healthcare. In that case, many planners recommend a lower withdrawal rate — closer to 3%–3.5% — to account for the longer horizon.
Retiring at 55 stretches your savings across more years and delays Medicare until 65, so how long my retirement money will last depends on a lower withdrawal rate.
What happens if I outlive my savings?
You would rely on Social Security, any pensions, and family support. To reduce this risk, some retirees convert part of their savings into an annuity or delay claiming Social Security. Longevity insurance — a deferred income annuity starting at age 80 or 85 — is one option worth exploring with a fiduciary advisor.
Converting part of your savings into an annuity or delaying Social Security can reduce the risk of outliving your savings and extend how long my retirement money will last.
Does where I live affect how long my retirement money will last?
Absolutely. State income taxes, property taxes, and cost of living vary widely. Moving from a high-cost metro to a lower-cost region can reduce annual spending by thousands of dollars, effectively lowering your required withdrawal rate without touching your portfolio strategy.
How often should I recalculate how long my retirement money will last?
At least once a year, and after any major life event — a market crash, a health diagnosis, a home sale, or an inheritance. A single recalculation in your first retirement year catches sequence-of-returns problems while you still have time to adjust spending.
Should I include my home equity when estimating how long my retirement money will last?
You can, but treat it conservatively. A home only extends your runway if you're willing to downsize, rent it out, or use a reverse mortgage. If you plan to stay put and pass the home to heirs, exclude it from your spending math to avoid a false sense of security.
Conclusion
So — how long my retirement money will last is no longer an unanswerable question. Here are the key takeaways:
- Your runway depends on three numbers: savings, annual spending gap, and real returns
- The 4% rule is a solid baseline, but flexible withdrawals often perform better
- Inflation, healthcare costs, and market timing in early retirement are your biggest risks
- Delaying Social Security and spending one less year in retirement are the two most powerful levers you control
Don't leave your answer to chance. Set aside 30 minutes this week, gather your account balances and expense estimates, and run them through the Fidelity Retirement Score or a similar calculator — knowing how long my retirement money will last is the first step to making it last longer.
