How long will my investments last in retirement depends on three levers: your withdrawal rate, your asset mix, and your spending. The Employee Benefit Research Institute's long-running Retirement Confidence Survey has repeatedly found that a large share of workers retire with far less saved than they expect to need, often under $100,000 in personal savings.
That gap turns a simple math question into a planning problem. This guide walks you through the withdrawal math, the role of market returns and inflation, sequence-of-returns risk, and the tools that model it all. You will finish with a realistic framework and a few concrete steps you can take today.
Start With the Withdrawal Rate, Not the Balance
The fastest way to estimate how long will my investments last in retirement is to divide your portfolio by your annual withdrawal. A $750,000 portfolio withdrawing $30,000 a year implies a 4% withdrawal rate.
The widely cited "4% rule," drawn from the Trinity study by three finance professors in the 1990s, suggested that a 4% initial withdrawal, adjusted for inflation, historically lasted 30 years in most rolling periods.
That rule is a starting point, not a guarantee. Later research, including work from Morningstar and updates to the original study, shows outcomes vary widely depending on market conditions in your first decade of retirement. A 4% rate on a 50/50 stock-bond mix is far safer than the same rate on an all-cash portfolio.
- Lower withdrawal rates buy time. Dropping from 4% to 3.5% can add several years of portfolio life in most historical simulations.
- Higher rates shrink the runway fast. At 6% or more, many historical scenarios depleted the portfolio within 20 to 25 years.
- Your time horizon matters. A 30-year retirement needs a different rate than a 40-year one.
How to apply this: calculate your current withdrawal rate by dividing annual spending by total investable assets, then stress-test it at 3%, 4%, and 5%.
Factor In Returns, Inflation, and Fees
Nominal returns tell you little; real, after-fee returns tell you almost everything about how long will my investments last in retirement. If your portfolio earns 6% and inflation runs at 3%, your real return is roughly 3%. Subtract a 0.5% advisory or fund fee and you are down to about 2.5%.
That difference compounds into years of portfolio life over a 30-year horizon.
Vanguard's research on the "cost matters hypothesis" has long shown that lower-cost funds tend to outperform higher-cost equivalents over time, precisely because fees eat into compounding. The SEC's investor education materials make a similar point, warning that even a 1% annual fee can meaningfully reduce a portfolio's ending value over decades.
Inflation is the quieter risk. A 3% inflation rate halves purchasing power in roughly 24 years, so a $60,000 annual budget today needs about $120,000 in 24 years to buy the same goods. That reality is why many planners model spending in real terms rather than nominal dollars.
- Use real returns in your model. Subtract expected inflation from expected returns before projecting.
- Track your all-in cost. Include fund expense ratios, advisory fees, and trading costs.
- Revisit assumptions annually. Return expectations shift with interest rates and valuations.
How to apply this: pull your portfolio's weighted expense ratio from your brokerage statement and subtract it from your assumed return before running any projection.
Understand Sequence-of-Returns Risk
Two retirees with identical average returns can end up with wildly different outcomes depending on the order of those returns. This is sequence-of-returns risk, and it is the single biggest reason simple average-return math overstates how long will my investments last in retirement.
A market crash in your first few retirement years forces you to sell assets at depressed prices to fund spending, permanently reducing the base that later needs to recover. A crash in year 20 hurts far less because most of the spending is already behind you.
Research from Wade Pfau and other retirement researchers consistently shows that early-retirement returns drive outcomes more than long-run averages.
- Hold a cash buffer. Keeping one to two years of spending in cash or short-term bonds avoids forced selling in a downturn.
- Use a rising equity glide path. Some planners recommend starting retirement with a slightly lower stock allocation and increasing it over time.
- Consider a dynamic withdrawal strategy. Reducing spending after a bad year can extend portfolio life substantially.
A common scenario: a retiree withdrawing 4.5% who hits a 30% market decline in year two may see their sustainable rate fall below 3.5% almost overnight. A cash buffer and flexible spending rule soften that blow.
How to apply this: set aside 12 to 24 months of expected withdrawals in a stable, liquid account before you retire, so a bad market year never forces you to sell stocks at a low.
Model Your Plan With Real Tools
Spreadsheets work, but dedicated retirement calculators handle sequence risk, taxes, and inflation more reliably when you want to know how long will my investments last in retirement. A few established options are worth knowing.
- FIRECalc runs your portfolio against historical market data to show how many past starting years would have funded your spending plan.
- Vanguard's Retirement Income Modeler projects income across different market scenarios and lets you test spending changes.
- Fidelity's Retirement Planning tools include a savings and income estimator that factors in Social Security timing.
These tools are not crystal balls, but they turn a vague question into a range of outcomes you can plan around. Run each one with conservative assumptions and compare the results.
| Factor | What it tells you | Action to take |
|---|---|---|
| Withdrawal rate | Annual spending as % of portfolio | Keep it at or below 4% |
| Real return | Growth after inflation and fees | Model 2.5%–3.5% real |
| Sequence risk | Early-year market impact | Hold 1–2 years in cash |
| Time horizon | Years your money must last | Plan for 30–40 years |
| Spending flexibility | Room to cut in bad years | Set a 10% cut rule |
| Tax drag | Taxes on withdrawals | Coordinate account types |
| Social Security timing | Delay boosts lifetime income | Model claiming at 67–70 |
How to apply this: run your plan through at least two calculators and compare the worst-case outcomes, not the averages.
Build in Flexibility and Review Annually
No projection survives contact with reality unchanged. The most reliable way to extend how long will my investments last in retirement is to build in flexibility and revisit the plan every year.
A simple annual review catches drift before it becomes a crisis. Check your actual spending against the plan, rebalance your allocation, and rerun the projection. If the market had a strong year, you may be able to raise spending slightly or refill your cash buffer. If it had a weak year, trim discretionary spending.
- Set a spending floor and ceiling. Know the minimum you need and the ideal you want.
- Rebalance once a year. This enforces selling high and buying low without emotion.
- Refill the cash buffer after good years. It is your shock absorber for the next downturn.
The 4% rule and similar frameworks are guides, not contracts. Treat your withdrawal rate as a dial you adjust based on how the portfolio performs.
How to apply this: schedule a fixed date each year to review spending, rebalance, and rerun your projection, and write down the spending cut you would make if the portfolio drops 20%.
Frequently Asked Questions About how long will my investments last in retirement
How do I estimate how long will my investments last in retirement if I have a pension?
Add your pension as a fixed income stream and model only the gap between total spending and pension income. A retiree with a $40,000 pension and $70,000 of spending only needs the portfolio to cover $30,000, which can extend how long will my investments last in retirement by many years.
What happens to my timeline if I retire during a market downturn?
A poor first year can shorten your timeline more than a poor tenth year. Holding a cash buffer and cutting discretionary spending for one or two years often protects the portfolio enough to restore the original timeline for how long will my investments last in retirement.
Does delaying Social Security change how long will my investments last in retirement?
Yes, often dramatically. Each year you delay claiming past full retirement age raises your benefit by roughly 8%, reducing the draw on your portfolio. For many retirees, bridging the gap from savings to age 70 extends how long will my investments last in retirement by several years.
How does long-term care risk affect the projection?
A single extended care event can cost well over $100,000 and is not captured in standard models. Reserving a separate bucket or buying long-term care insurance protects the core portfolio and keeps your estimate of how long will my investments last in retirement realistic.
Can I use a bucket strategy instead of a single withdrawal rate?
Yes. Splitting assets into short-term cash, medium-term bonds, and long-term stocks lets you spend from stable buckets during downturns. Many retirees find this easier to follow than a fixed percentage, and it often improves how long will my investments last in retirement in stress tests.
Conclusion
The answer to how long will my investments last in retirement comes down to a handful of controllable factors.
- Withdrawal rate drives everything. Staying near 4% or below buys decades of runway.
- Real returns after fees and inflation matter more than headline returns.
- Sequence risk is real. A cash buffer and flexible spending protect against bad early years.
- Review annually. Small adjustments beat dramatic fixes later.
Your next step is simple: calculate your current withdrawal rate today, run it through one historical calculator like FIRECalc, and write down one spending rule you would follow if markets turn. That single exercise turns a stressful unknown into a plan you can manage.
