Wondering if your retirement savings will actually last?
This free simulator runs 2,000 scenarios against a century of real market data to show you the probability your money survives your lifetime. This is not just a generic estimate, but a result built around your specific numbers and sophisticated modeling. Unlike tools from financial advising firms that lock the real analysis behind an advisor call, this one puts the full model in your hands.
DIY Retiree — Retirement Probability Simulator
Retirement Probability Simulator
Enter your household details to model how likely your savings will last through retirement, based on historical market return distributions.
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Your results will appear here
Fill in your details on the left and click Run simulation to model your retirement probability across 2,000 scenarios.
Simulation methodology
Important Disclosure: This tool is provided by DIY Retiree (diyretiree.com) for educational and illustrative purposes only and does not constitute financial, investment, tax, or legal advice. Results are hypothetical projections based on user-provided inputs and statistical modeling — they are not guarantees of future performance. Returns are simulated using historical market data (1926–2025) or forward-looking parametric assumptions; past performance does not guarantee future results. This tool does not account for all factors relevant to your individual situation, including state taxes, estate planning, debt obligations, or changes in law. Social Security projections assume current benefit levels, which are subject to legislative change. DIY Retiree is not a registered investment advisor, broker-dealer, or licensed financial planner, and nothing on this page constitutes a solicitation or recommendation to buy or sell any security. Please consult a qualified financial advisor, CPA, or attorney before making any financial decisions.
In other models, financial planners often consider a 75-80% success rate adequate. This tool tends to be more conservative in the way the model is set up, so your success rate may read slightly lower than what you’ve seen elsewhere. That should actually give you confidence in this model. Ultimately this model helps with other components that most calculators lack: end of life care modeling, retirement spending throughout retirement, pre-Medicare healthcare costs, extra expenses for the first ten years, or extra income through certain periods after retirement. As you work through the tool, note both the median results and the lower tail to determine potential failure points along the way. You’ll see that generally, the longer your time horizon, the more potential failure points as the model links together consecutive periods of low returns. The opposite is true, of course, and you’ll find longer periods also allow the model to chain together consecutive periods of high returns as well. This provides, in one page, one series of inputs, and a robust output for you to consider your current retirement numbers
How much do I need to retire?
This tool helps answer this question. The models used are sophisticated and the inputs flexible but important. In looking at your retirement, do you see a dramatic drop at some point in the median scenario? If so, there is usually an inflection point where your remaining savings are not covering your monthly expenses. Why is that? Is there a way to adjust your current savings, your anticipated expenses in retirement that change your success rate significantly? You can play with the defaults here, but you’ll find that the biggest changes are driven by your personal financial behavior: how long you work, how much you save along the way, and how you manage your expenses. While this can be daunting initially, this is ultimately the most empowering aspect of personal financial planning.
Will my savings last through retirement?
The old-school standard answer is that if your savings are 25 times your annual expense needs, the answer is yes. That answer can be frustrating because it’s overly simplistic and doesn’t include a whole host of other considerations. This probability calculator helps with that with additional simple inputs. It also has a sophisticated modeling engine that rivals established investment firms’ approach. Using this calculator, you can stress-test both models against your specific situation and see exactly where potential failure points emerge.
What is a Safe Withdrawal Rate?
A Safe Withdrawal Rate (SWR) is equal to how much you can withdraw each year from your portfolio without running out of money in your lifetime. The 4% rule has been recently revised by Bill Bengen to 4.7%, so even the originator of that rule has changed it (and incidentally, even at the start it was 4.1%, not the 4% commonly used). However, retirees are often frustrated by this because during your “go-go” years you want to go DO things, and you’re more physically able to do so. That means your expenses go UP during this period. Retirement withdrawals aren’t a “flat” spending pattern, but using this probability calculator you can customize your spending approach with better precision than is available in most tools.
Tony Markey, MBA, founded DIY Retiree to provide free retirement planning tools and straight-talk guidance for pre-retirees managing their own financial futures.