When Can I Retire Calculator: Odds Across 1,000 Futures

3.9%. Morningstar's 2025 research found that this starting withdrawal rate held up in 90% of simulated futures over a 30-year retirement. Notice what that number measures. It doesn't assume steady growth or an average year. It's a success rate. So if you're looking for a when can I retire calculator, look for that kind of answer too. A single age isn't enough. You want the odds that your money lasts if you stop working at that age. (Source: Morningstar, The State of Retirement Income 2025, Dec 2025.)

Here's the short answer to "when can I retire?" You can retire once your savings, set against your monthly spending, keep you funded in a high share of possible futures, running all the way to your 90s. The rest of this article covers how to measure that, and why most calculators skip the measuring.

The short answer: you can retire when the odds are on your side

Most retirement calculators answer a different question from the one you're asking. They ask: if markets return a fixed percentage every year, when do I reach my target?

That's a fair place to start. Fort Pitt Capital's retirement age calculator gives a typical example: a 30-year-old with $50,000 saved, adding $500 a month at a 7% return toward a $1 million goal, could retire around 60 (Fort Pitt Capital).

That tells you when you might hit a number. It doesn't tell you if the number will last. Real markets don't pay 7% every year. They go up 20%, drop 15%, sit flat, and then recover. The order those years come in can matter as much as the average.

So the real answer to "when can I retire?" sounds more like this:

• If you retire at this age and spend this much each month, X out of 1,000 possible futures stay funded.

That's a probability, not a promise. It's also a far more honest place to start.

How a typical when can I retire calculator works, and where it breaks

Most retirement age tools ask for the same handful of inputs (Accurate Calculators):

• Current age
• Current savings
• Yearly contributions
• Expected rate of return
• How long retirement lasts
• The income you want

Then they grow your savings at one steady rate and give you back one age. Clean. Simple. And fragile in three ways.

1. They assume a smooth ride. A fixed return can't show sequence-of-returns risk. That's the idea that a market crash in your first few years of retirement does far more damage than the same crash ten years in, because you're selling investments to live on while prices are low.

2. They stop at the finish line. Some tools, especially early-retirement (FIRE) calculators, model only the years you're saving. They tell you when you can stop working, but they don't check whether your withdrawals actually last afterward (Engaging Data).

3. They hide how much the assumptions matter. In one analysis, the same 4% withdrawal plan showed a success rate above 95% under bullish return assumptions and just 62% under pessimistic ones (Advisor Perspectives, "The Dangers of Monte Carlo Simulations," Jan 2023). Same plan, very different picture. A calculator that shows only one number hides that range from you.

What "1,000 simulated futures" actually means

Monte Carlo simulation sounds technical. The idea is simple.

Rather than assuming one market path, the engine plays out your retirement many times. Each run uses a different random mix of good years, bad years and ordinary years. Some futures start with a crash. Some start with a boom. Most land somewhere in between.

Then it counts. In how many of those futures does your money last?

If 900 of 1,000 stay funded, your success rate is 90%. That's the same standard Morningstar used to land on its 3.9% figure: was the money still there in 90% of simulated outcomes?

It helps to know where the famous "4% rule" came from. The Trinity Study found a 95% success rate over 30 years for a 50/50 portfolio of U.S. large-cap stocks and long-term corporate bonds. It got there by testing rolling historical periods, not by Monte Carlo simulation (Advisor Perspectives). History and simulation are both useful. But neither one is a guarantee.

The three numbers that drive the answer

You don't need a spreadsheet to get a first answer. You need three numbers:

1. Your age. This sets how many years your money has to cover.
2. What you've saved for retirement. This is the pool you'll draw from.
3. What you spend each month. This is the number most people have never pinned down.

That last one matters more than it seems. EBRI's 2025 Retirement Confidence Survey found that only 52% of workers have estimated the monthly income they'll need in retirement. The other 48% are guessing (Source: EBRI/Greenwald, Retirement Confidence Survey 2025, Fact Sheet 3).

If you don't know your monthly spending, start there. Look at your last few months of bank and card statements. A rough honest number beats a precise made-up one.

Four risks your retirement date has to survive

A retirement age only works if the plan behind it can handle the things retirement throws at you. These four come up again and again.

Longevity: plan for a long life

Social Security's own planning guidance says about one out of every three 65-year-olds may live until at least age 90 (Source: Social Security Administration, Retirement Information for Medicare Beneficiaries, 2026). That's why the plan you build with Monte Climb runs to age 95 by default, and you can push it further.

Health care: count it year by year

Fidelity estimates that a 65-year-old retiring in 2025 will spend $172,500 on Medicare premiums, deductibles and prescriptions over retirement. That figure leaves out long-term care entirely (Source: Fidelity Investments, 2025 Retiree Health Care Cost Estimate, Jul 2025). Our engine charges Medicare premiums and income-based surcharges year by year rather than plugging in one flat guess.

If you're thinking about retiring before 65, there's one more thing to plan for: Medicare doesn't start until then. Many calculators skip health care altogether. Merrill's, for example, excludes health care and long-term care costs (Merrill Edge).

Retiring earlier than you planned

This one surprises people. According to the Allianz Life 2026 Retirement Study, as reported by 247 Wall St., 42% of retirees left work earlier than planned, 53% retired around when they expected, and only 5% retired later. EBRI's 2025 survey found a median expected retirement age of 65 and a median actual age of 62, as reported by Clark.com.

What does that mean for you? Don't test only the age you hope for. Test a few years earlier, too. "Can I retire at 62?" is worth asking even if you plan to work until 66.

Your Social Security age is not your retirement age

A lot of people searching "when can I retire" really want to know their full retirement age for Social Security. Those are two separate questions.

• Full retirement age runs from 65 to 67 depending on birth year. It's 67 for anyone born after 1959 (Capital Group).
• You can start benefits at 62 at a reduced amount, and your benefit keeps growing if you wait, up to age 70.
• The SSA's official calculators estimate your benefit at each claiming age from 62 to 70 (USA.gov).

You can stop working at one age and claim Social Security at another. When you retire depends on whether your savings can cover the gap.

The honest limits of any simulation

Monte Carlo is a better tool than a single average. It isn't a crystal ball.

• The inputs shape the output. Change the return assumptions and the success rate moves, sometimes by a lot, as the Advisor Perspectives example shows.
• Extreme crashes can be underrated. Simulations that assume returns follow a normal bell curve can understate how often events like 1929 or 2008 happen (FFF Instill).
• Life isn't a model. Health, family and job security don't follow random number generators.

So treat any success rate as a guide to judgment. It doesn't replace your judgment.

How to use your answer

Once you have a success rate, here's a steady way to work with it:

1. Get your baseline. Enter your age, savings and monthly spending as they are today.
2. Test the earlier date. Ask what happens if you stop work a few years sooner than planned.
3. Adjust one lever at a time. Spend a little less, work a little longer, or save a little more, then watch how the odds change.
4. Ask why. A number with no explanation is hard to trust. You should be able to see what's driving it.

That last step is where William, our AI planner, comes in. You can talk to him like you would a friend and ask things like "Am I on track?", "Can I retire at 62?" or "What's a sustainable spend for me?" He shows his work. And since this is planning software, not advice, the goal is to help you understand your own numbers, not to tell you what to do.

Run your own numbers

When can you actually retire? The honest answer is a probability, and you can get yours from three numbers.

The Monte Climb retirement calculator runs your savings through 1,000 simulated futures, the same engine behind the app, and gives you one clear success rate. It runs in your browser, and nothing is saved until you say so. If you want to go further, the full Monte Climb planning app comes with a 7-day trial for $1.

Three numbers. One clear answer. Show my answer →

How to compare online retirement calculators

Finance news sites, banks, brokers and planning apps all offer free retirement calculators. Many look alike, but they can answer very different questions. A few checks show what a tool is actually measuring.

• Does it use one return or many? A tool that grows your savings at a single fixed rate, such as 7% a year, gives you one clean age. It can't show what happens when bad years come early. A tool that runs many market paths, like 1,000 simulated futures, can show that.
• Does it go past your retirement date? Some calculators stop on the day you reach a savings target. Others keep going and check whether your withdrawals last through a 30-year retirement or longer.
• Does it give a success rate? An answer like "funded in 90% of futures" says more than "retire at 60," because it shows how much room for error the plan has.
• Can you see and change the assumptions? The same 4% withdrawal plan can look above 95% safe or close to 62%, depending on the return assumptions. A tool that hides its inputs hides that range too.
• Does it count spending you can't avoid? Health care costs, a long life and when you claim Social Security all change the answer.

Monte Climb is built around these questions. Its results come as odds across 1,000 futures, not one fixed age.

Frequently asked questions

How does a when can I retire calculator work?

Most of them take your age, savings, contributions and an expected return, then grow your savings at one fixed rate until you reach a target. A Monte Carlo calculator works differently. It runs your plan through many simulated market paths and tells you what share of those futures keep your money funded.

What is a good success rate for a retirement plan?

No single number is right for everyone. Morningstar's 2025 research used a 90% standard: whether money was still there in 90% of simulated outcomes over 30 years. That's how it arrived at a 3.9% safe starting withdrawal rate. A success rate is a probability, not a guarantee.

Is my Social Security full retirement age the same as when I can retire?

No. Full retirement age is 65 to 67 depending on your birth year, and 67 for anyone born after 1959. You can claim reduced benefits from 62, and your benefit grows if you wait, up to 70. You can stop working at one age and claim at another, as long as your savings can cover the gap.

How long should my retirement plan last?

Longer than you might expect. The Social Security Administration says about one in three 65-year-olds may live to at least 90. That's why many planners, Monte Climb included, run plans to age 95 by default.

Should I plan to retire earlier than I expect?

It's worth testing. The Allianz Life 2026 Retirement Study, as reported by 247 Wall St., found that 42% of retirees left work earlier than planned. Check how your plan holds up a few years before your target date, as well as at the date itself.