How Long Will Savings Last in Retirement Calculator Guide

Most retirement calculators hand you a single age when your money runs out. Age 86. Age 91. It looks precise, but it isn't. A good how long will savings last in retirement calculator should give you a more honest answer: the chance your money lasts across many possible futures. This guide covers how these tools work, where the common ones fall short, and how to read the answer once you have it.

The short answer

How long your savings last depends on four things:

• How much you have saved.
• How much you spend each month.
• How many years the money has to cover.
• The order in which markets deliver good and bad years.

The first three are easy to enter into a calculator. The fourth is where most tools stop being useful.

A benchmark helps here. Morningstar's latest research puts the highest safe starting withdrawal rate at 3.9%. That figure means withdrawing 3.9% of your portfolio in year one and adjusting for inflation after that. Morningstar didn't judge it by average returns. It judged it by whether money was still left in 90% of simulated outcomes over a 30-year retirement.

Source: Morningstar, The State of Retirement Income 2025, December 2025.

The benchmark is framed as a success rate, not a promise. Your own plan should be read the same way.

How a how long will savings last in retirement calculator usually works

Most of the tools that rank for this search follow the same pattern. You enter some numbers and get back a number of years or a depletion age.

Typical inputs include:

• Current savings balance
• Monthly or annual withdrawal
• Expected rate of return
• Inflation
• Retirement age and life expectancy
• Other income, such as Social Security or a pension

The US News retirement calculator asks for age, income, savings and contributions, along with inflation and optional rates of return. The USAA Educational Foundation tool factors in savings, spending, income, expected return and inflation.

These tools are helpful, and they are a reasonable first step. Most of them share one quiet assumption, though: the market returns the same amount every year.

For example, retirementbudget.org bases its results on a 5% nominal return with withdrawals rising 2.5% a year. Its sensitivity table shows how much spending matters. In its example, raising withdrawals from $4,000 to $5,000 a month moves the depletion age from 86 to 80.

howlongsavingslast.com estimates that $1 million withdrawn at 4% a year, rising with inflation, tends to last around 38 years under typical assumptions. The site also says plainly that taxes, fees and market volatility are not included.

That candor is fair. It also shows the limit of the method. Real markets don't move in a straight line, and a straight-line answer can look more reassuring than it should.

Why one depletion age can mislead you

The missing piece is sequence of returns risk. Boldin defines it as the danger that poor returns early in retirement shrink your savings more than the same losses would later, even when the long-term average checks out.

Source: Boldin, Sequence of Returns Risk: How to Protect Your Savings.

Picture two retirees with the same savings, the same spending and the same average return over 30 years.

• Retiree A gets the good years first. Withdrawals come out of a growing balance.
• Retiree B gets the bad years first. Withdrawals come out of a falling balance and lock in losses before the recovery arrives.

A fixed-return calculator gives both of them the same depletion age. In real life, Retiree B can run short years earlier. The average return is the same in both cases. Only the order of the years is different.

So a single age doesn't tell you much. You need to know how many of the possible orderings still work.

What Monte Carlo means, in plain English

Monte Carlo is a name for a simple idea: run the plan many times, with different market paths, and count the results.

It works like this:

1. Take your savings, your age and your monthly spending.
2. Generate one possible future, a sequence of good, bad and middling years.
3. Check whether your money lasts through the whole plan.
4. Do it again with a different sequence. Then again, a thousand times.
5. Count how many futures stayed funded.

Suppose 870 out of 1,000 futures still have money at the end. Your success rate is 87%. That number is not a forecast of what will happen. It describes how robust your plan is across the range of what could happen.

The withdrawal rate benchmark: 3.9%, not 4%

You've probably heard of the 4% rule. The idea is that you withdraw 4% of savings in your first year and adjust for inflation afterward, and your money should last around 30 years (The Motley Fool, 2019).

Morningstar's current research updates that number every year:

• 3.9% is the base case for a fixed, inflation-adjusted withdrawal with a 90% probability of money remaining after 30 years.
• 3.7% was the previous year's figure (Yahoo Finance).
• Up to 5.7% is possible with more flexible approaches, such as delaying Social Security, using spending guardrails, or including Treasury Inflation-Protected Securities (TIPS).

Source: Morningstar, What's a Safe Retirement Withdrawal Rate for 2026?

Guardrails means your spending moves within set limits. You trim a little after bad years and allow a little more after good ones. Flexibility like that is one of the biggest levers you have.

Quick self-check: multiply the monthly spending you need from savings by 12, then divide by your savings. Spending $4,000 a month from $1.2 million works out to $48,000 a year, which is a 4% withdrawal rate. That's close to the benchmark, but slightly above it.

This arithmetic is a rough check, not a verdict. Your age, your time horizon and your other income all change the picture.

Three risks a good calculator should account for

1. Living longer than you planned

About 1 in 3 65-year-olds may live to at least age 90, according to the Social Security Administration's planning guidance.

Source: Social Security Administration, Retirement Information for Medicare Beneficiaries, 2026.

A plan that stops at 85 quietly bets against a third of retirees. That's why the plan you build with Monte Climb runs to 95 by default, and you can push it further.

2. Health care costs

Fidelity estimates a 65-year-old retiring in 2025 will spend $172,500 on Medicare premiums, deductibles and prescriptions over retirement. That figure excludes long-term care entirely.

Source: Fidelity Investments, 2025 Retiree Health Care Cost Estimate, July 2025.

That is a real line item. Our engine charges Medicare premiums and income-based surcharges year by year instead of using a flat guess.

3. Bad timing

This is sequence risk again. You can't control when markets fall. You can see how your plan holds up if they fall early, which is the whole point of simulating many futures.

How to read your result

Once you have a success rate, the useful question becomes: what moves it?

• Spending. Small monthly changes add up over decades, as the depletion tables above show.
• Retirement age. Working a little longer means more saving and fewer years of withdrawals.
• Flexibility. Morningstar's research suggests flexible approaches can support higher starting withdrawals than a rigid rule.
• Time horizon. Planning to 95 instead of 85 lowers your success rate on paper. It also brings it closer to reality.

There's no universally right success rate. Morningstar uses 90% as its benchmark. Some people are comfortable with less if they can cut spending in a bad stretch, and others want more cushion. That's a personal trade-off, and this is planning software, not advice.

A useful habit is to break your plan on purpose, before life does. Raise your spending, retire a few years earlier, or extend the plan to 100. Then watch what happens to the odds.

Run your own numbers

Here's a striking figure. In EBRI's 2025 Retirement Confidence Survey, 48% of workers said they had never estimated the monthly income they'll need in retirement.

Source: EBRI/Greenwald, Retirement Confidence Survey 2025, Fact Sheet 3.

You can take that first step in under a minute. The calculator needs three numbers: your age, what you've saved for retirement, and what you spend each month. We run them through 1,000 simulated futures using the same engine behind the app, and return one clear answer, the share of futures that stay funded.

It runs in your browser, and nothing is saved until you say so. If you want to go further, you can ask William, our AI planner, questions like Am I on track?, Can I retire at 62? or What's a sustainable spend? He shows his work.

The answer you get is a probability, not a promise. It's still a far better starting point than a guess.

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Frequently asked questions

How long will $1 million last in retirement?

It depends on how much you withdraw and how markets behave. One fixed-return calculator, howlongsavingslast.com, estimates that $1 million withdrawn at 4% a year, rising with inflation, tends to last around 38 years under typical assumptions. It does not model market volatility. A Monte Carlo calculator shows how often that spending survives across many different market paths, which is a more realistic answer.

What is a safe withdrawal rate in retirement?

Morningstar's latest research puts the safe starting withdrawal rate at 3.9% for fixed, inflation-adjusted spending, based on a 90% chance of money remaining after 30 years. With flexible strategies such as guardrails or delaying Social Security, Morningstar finds starting rates of up to 5.7% can work. Morningstar updates these figures annually.

What is a good success rate for a retirement plan?

No single number is right for everyone. Morningstar uses 90% as its benchmark for a safe withdrawal rate. Some people accept a lower rate if they can cut spending during bad years, and others want more cushion. Treat the success rate as a way to compare trade-offs, not as a guarantee.

Why do retirement calculators plan to age 95?

Longevity risk is real. Social Security Administration guidance notes that about one in three 65-year-olds may live to at least 90. A plan that ends at 85 can understate how long your money needs to last. Monte Climb plans run to 95 by default, and you can extend them.

Does the Monte Climb calculator save my information?

No. The calculator runs in your browser, and nothing is saved until you choose to save it. You enter your age, retirement savings and monthly spending, and it returns the share of 1,000 simulated futures in which your money stays funded.