Retirement Income Calculator: Will Your Savings Last 30 Years?

Picture this: You retire at 65 with $750,000 saved. You feel cautiously confident. But ten years later, at 75, you start to notice the balance dropping faster than expected. By 82, the account is empty. You are healthy, sharp, and have potentially another decade or more ahead of you, but the money is gone.

This is not a scare story. It is a mathematical reality that plays out when withdrawal rates, investment returns, and retirement length are not carefully matched. The encouraging part is that understanding the numbers in advance can make all the difference.

This article walks through three realistic withdrawal scenarios for a $750,000 portfolio, shows you exactly where the financial cliff appears, and explores the levers that could help you avoid it. Think of it as a guided tour through the kind of analysis a retirement planning review should always include.

At its heart, a retirement income calculator is solving one equation: how long will my money last if I withdraw a set amount each year, earn a certain return on what remains, and face rising costs from inflation?

The variables that matter most are:

• Starting portfolio balance (in our scenarios, $750,000)
• Annual withdrawal amount (expressed as a percentage of the starting balance)
• Investment return (what your remaining money earns each year)
• Inflation rate (how much your withdrawals grow each year to maintain purchasing power)
• Other income sources (Social Security, pensions, part-time work)

Change any one of these and the outcome shifts dramatically. That is what makes retirement income planning both powerful and, frankly, a little humbling. A small difference in withdrawal rate today can mean the difference between financial security at 90 and running out of money at 80.

One concept worth understanding before diving into the numbers is sequence of returns risk. Even if your average annual return over 30 years looks fine on paper, a string of bad market years in your first five years of retirement can permanently damage your portfolio, because you are selling shares at low prices to fund withdrawals, leaving fewer shares to recover when markets rebound. Simple calculators using flat average returns often miss this entirely.

The following scenarios are illustrative examples only, using a hypothetical retiree who retires at age 65 with $750,000 in savings. They assume a moderate portfolio earning approximately 6% annually on average, with withdrawals adjusted upward by 2.5% each year to account for inflation. These are simplified projections, not guarantees. Real outcomes depend on actual market performance, tax treatment, spending changes, and other personal factors.

Scenario 1: 3.5% Withdrawal Rate ($26,250 per year to start)

At 3.5%, our hypothetical retiree withdraws roughly $26,250 in year one, increasing modestly each year for inflation. In this scenario, projections suggest the portfolio remains intact well past age 95 in most moderate-return environments. This rate is below the widely discussed 4% guideline and tends to provide a meaningful cushion against bad market years. The trade-off is that $26,250 annually may feel tight, particularly before Social Security kicks in at a higher level.

Scenario 2: 4% Withdrawal Rate ($30,000 per year to start)

The 4% withdrawal rate became a widely cited benchmark after research by financial planner William Bengen in 1994, which suggested that a 4% annual withdrawal from a balanced portfolio had historically lasted at least 30 years in most historical market periods. At $30,000 per year from a $750,000 starting balance, this scenario provides more spending flexibility. However, it is worth noting that Bengen's original research was based on specific historical US market conditions, and some researchers and planners have since suggested that lower rates may be more appropriate in a world of lower expected bond returns. The 4% rule is a useful starting point, not a guarantee.

Scenario 3: 5% Withdrawal Rate ($37,500 per year to start)

Here is where the cliff becomes visible. At 5%, the hypothetical retiree withdraws $37,500 in year one. In a low-return environment or after a rough sequence of early market returns, projections suggest this portfolio could be substantially depleted by the early-to-mid 80s, potentially running dry around ages 82 to 85. In a favorable market environment it may last longer, but the margin for error is thin. A market downturn in years two through five of retirement at this withdrawal rate could accelerate depletion significantly.

The table below summarizes the estimated portfolio longevity under each scenario, assuming a 6% average annual return and 2.5% annual withdrawal inflation adjustment. These are rough illustrations only:

• 3.5% withdrawal ($26,250/year): Portfolio likely persists to age 95+ in moderate return environments
• 4.0% withdrawal ($30,000/year): Portfolio typically lasts 28-32 years under favorable to moderate conditions
• 5.0% withdrawal ($37,500/year): Portfolio may be depleted in 18-22 years, particularly if early returns are poor

Here is something that does not always get enough attention in withdrawal rate conversations: the more guaranteed income you have from sources like Social Security, the less pressure you place on your investment portfolio.

According to the Social Security Administration, claiming benefits at age 70 versus age 62 results in a benefit that is approximately 76% higher, assuming the claimant has a full retirement age of 67. For someone whose full retirement age benefit would be $1,800 per month, that means roughly $1,548 per month at 62 versus approximately $2,232 per month at 70 (before cost-of-living adjustments). Over a long retirement, this difference is substantial.

In practical terms, delaying Social Security often means drawing more heavily from savings in your early retirement years. But it also means that once the higher benefit begins, you can significantly reduce your portfolio withdrawal rate, which protects the portfolio in the years when sequence of returns risk is greatest. Our Social Security benefit estimator can help you think through the timing trade-offs at different claiming ages.

For a hypothetical retiree with $750,000 who delays Social Security to age 70 and receives an additional $600 per month ($7,200 per year) compared to claiming at 62, that extra income could effectively reduce the required portfolio withdrawal by roughly 24% annually. In scenario terms, that might shift someone from a 5% withdrawal rate down toward 4% or even 3.5%, which has a dramatic effect on portfolio longevity.

The 6% average return used in the scenarios above is a modeling assumption, not a promise. What your portfolio actually earns depends heavily on how it is invested, and how it is invested should reflect both your time horizon and your ability to tolerate short-term losses.

Broadly speaking:

• Higher equity allocations (more stocks) have historically produced higher average long-term returns but also larger short-term swings. A portfolio down 25% in year two of retirement at a 5% withdrawal rate is a very different situation than the same portfolio down 25% in year 15.
• Higher fixed income allocations (more bonds) have historically produced lower average returns but with less volatility. This can reduce sequence of returns risk but may also lower the sustainable withdrawal rate over a long retirement.
• Cash and near-cash holdings offer stability but typically lose ground to inflation over time.

Many financial planners explore a concept sometimes called a "bucket strategy," where near-term spending needs are kept in lower-risk assets and longer-term funds remain in growth-oriented investments. This is one way some retirees attempt to manage the tension between needing stability now and needing growth over decades. For a deeper look at how this balance works, exploring asset allocation options in retirement is a useful next step.

The key point for our scenarios: the same $750,000 portfolio will behave very differently depending on its investment mix, and a retirement income calculator that lets you adjust the assumed return is far more useful than one that uses a single fixed number.

If the scenarios above have raised some concerns about your own plan, the following are general approaches that people in or near retirement commonly explore. These are educational examples only, not personal recommendations. A qualified financial adviser can help assess which approaches, if any, are relevant to your circumstances.

1. Flexible spending in early retirement. Some retirees consider spending slightly less in the first five to seven years, when portfolio damage from market downturns is hardest to recover from. Spending flexibility in those years can meaningfully improve long-term outcomes.
2. Part-time income bridges. Even modest earned income in the early retirement years can reduce portfolio withdrawals significantly. Many people find that working part-time in retirement provides both financial and personal benefits during the transition period.
3. Delaying Social Security. As outlined above, higher guaranteed lifetime income from Social Security reduces the burden on the investment portfolio, particularly in later years when part-time work may no longer be feasible.
4. Roth conversions before retirement. Converting traditional IRA or 401(k) funds to Roth accounts during lower-income years can reduce future Required Minimum Distributions (which begin at age 73 under current IRS rules), potentially giving more control over taxable income and withdrawal sequencing in retirement.
5. Downsizing or home equity. For homeowners, home equity is often a substantial but overlooked asset. Some retirees explore downsizing to free up capital that can supplement the investment portfolio, though this decision involves both financial and emotional dimensions.

This article is for general educational purposes only. The scenarios and figures presented are illustrative hypothetical examples and are not personalized financial advice. Retirement income projections depend on many variables and actual outcomes may differ significantly. Please consult a qualified financial adviser, tax professional, or retirement planning specialist before making any financial decisions.