CalcMyRetirement

Free Monte Carlo Retirement Simulator With Historical Stress Testing

CalcMyRetirement is a free web-based retirement calculator that runs entirely in your browser. You provide your financial details, and it runs Monte Carlo simulations to stress-test your retirement plan against random market scenarios and historical bear markets. All calculation happens on your device, and no financial data is sent to any server.

The tool is built for one specific job: answering the question "Will my money last?" It starts with your current retirement balance, expected years in retirement, annual contributions, expected investment returns, and inflation assumptions. You choose your withdrawal method (either a fixed percentage of your portfolio each year or a fixed dollar amount, both adjusted for inflation or not). The calculator then runs Monte Carlo simulations to show the probability that your plan succeeds. It also lets you stress-test your plan against historical market crashes: the Great Depression (1929-1939), the 1970s stagflation period (1973-1982), or the Lost Decade (2000-2009). These historical stress tests use actual S&P 500 returns from those periods, excluding dividend reinvestment.

The interface is dense with options because the tool is designed for detail-oriented planning. You can choose to run 10,000, 50,000, 100,000, or 250,000 simulations. More simulations give more precise results but take longer to compute. You can switch between Monte Carlo (random market returns) or historical S&P 500 averages as your market model. You can toggle a dynamic spending model that adjusts your retirement spending by life phase: Go-Go years (start to age 75) spend 110% of baseline, Slow-Go years (75-85) spend 85%, and No-Go years (85+) spend 70% of baseline. This reflects the common pattern of higher spending early in retirement and lower spending later.

A spending guardrails feature is also available. Rather than a fixed withdrawal rate, guardrails automatically adjust your spending based on portfolio health. If your portfolio grows beyond an upper threshold (the site suggests 20% in its example), your spending increases by a step amount. If it falls below a lower guardrail (the site suggests 15% in its example), spending drops by the same step. This creates a flexible spending plan that bends with market conditions, often used in dynamic withdrawal strategies.

Money Comes In: Manual Entry, No Bank Links

CalcMyRetirement does not connect to banks or investment accounts. You manually enter your financial information: current account balances, expected annual contributions, expected investment returns, and inflation assumptions. The site states explicitly: "This calculator operates entirely in your web browser. We do not collect, store, or transmit any of your personal or financial information to remote servers." The application also does not use cookies or tracking mechanisms, so there is no persistent user profile across sessions.

The inputs are flexible. You can enter a current retirement balance, contributions before retirement starts, years until retirement, and expected years in retirement. For income sources, you can specify Social Security (the tool asks for your current age and Social Security start age, and you enter the yearly amount). Advanced options add part-time work income, rental income, pension income, and dividend yield from taxable accounts, each with their own line items. On the spending side, you can include estimated annual healthcare costs (in today's dollars), and the tool adjusts them forward with inflation.

The manual-entry approach means you control your data and it never leaves your device. The downside is that updates are manual. If your portfolio grows 30% in a year, you need to return to the calculator, update your balance, and re-run the simulation. There is no real-time link or automatic refresh.

How It Works: Simulation and Stress Testing

CalcMyRetirement centers on Monte Carlo simulation. After you input your scenario (balance, contributions, withdrawal strategy, income, expenses), the calculator runs simulations (up to 250,000) with randomized investment returns to show how often your plan succeeds. The results display a success rate (percentage of simulations where you do not run out of money), percentile outcomes (best, median, worst cases), and charts of portfolio balance over time.

A key differentiator is historical stress testing. Rather than relying on statistical models alone, you test your plan against real market conditions from three major downturns: the Great Depression (1929-1939), 1970s stagflation (1973-1982), and the Lost Decade (2000-2009). The calculator shows whether your plan would have survived using actual S&P 500 returns from those periods. This grounds the analysis in real historical events.

Results are detailed and visual. Year-by-year projections show starting balance, contributions, withdrawals, investment growth, Social Security income, and ending balance for each retirement year. Charts display portfolio balance, income versus expenses, Monte Carlo success distribution, and spending across retirement phases. The "funded ratio" chart shows how much of your goal you have already saved; conventional thinking targets 120-150% of retirement expenses in assets, and the tool visualizes how additional saving shows diminishing returns beyond that point.

Optional add-ons include a "Die With Zero" optimizer (specify your target end-of-life balance and life expectancy to find sustainable spending levels) and a Geographic Arbitrage Simulator (compare how relocating to a different state affects retirement costs). You can download results as Excel or PDF reports.

Pricing and What the Tool Includes

CalcMyRetirement is completely free. There are no paid tiers, subscriptions, trial periods, or premium features. All tools (Monte Carlo, historical stress tests, dynamic spending, guardrails, Social Security integration, advanced options) are available without cost. You can run unlimited simulations, download reports, and revisit your plan as often as you want.

The site's terms state the calculator is "for informational and educational purposes only" and not financial advice. Projections are "estimates only and are not guaranteed" and "actual investment returns may differ significantly." The creators disclaim liability for losses or damages. There is no user account and no data storage across sessions.

The geographic arbitrage feature's cost-of-living, tax, and healthcare estimates are subject to change and may not be current, so results should be verified with current sources before making relocation decisions. A feedback form is available for reporting bugs or requesting features.

Who This Suits and Who It Does Not

CalcMyRetirement is best for individuals comfortable with spreadsheet-style inputs who want detailed simulations without cost or advisory fees. If you understand Monte Carlo analysis and withdrawal rates, the tool offers rich insights. It excels at exploring scenarios: early retirement, different spending levels, market downturns.

The tool is less suitable for those seeking guidance on withdrawal strategy or plan soundness. The calculator provides results, not advice. Interpreting a 70% success rate requires financial literacy; different people draw different conclusions from the same numbers.

CalcMyRetirement does not store scenarios between sessions. If you close your browser, you start fresh the next time you visit. Building a long-term record of your plan requires saving reports manually. The geographic arbitrage simulator assumes cost differences are driven by state taxes and housing, but does not account for local variation or specific personal factors (job availability, family ties, healthcare access).

The tool is US-centric, modeling US Social Security, using the S&P 500 as the historical index, and assuming US state income taxes. International users or those planning to retire outside the US would need to manually adjust inputs. Copyright is held by Retirement Optimizers (2026).