Monte Carlo simulation is a technique that runs thousands of independent trials — each with randomly drawn market returns — to produce a probability distribution of outcomes rather than a single projection. Retirement Lab runs 10,000 simulated market paths for each scenario, giving you a realistic range of what could happen to your portfolio over time.
Retirement Lab models income tax, capital gains tax, and wealth tax across 31 supported countries, including the US, UK, Canada, Spain, Portugal, France, Germany, and more. Tax calculations use bracket-based models reflecting current published rates and thresholds. Tax models are simplified approximations — consult a qualified tax professional for your specific situation.
Tax calculations use real bracket-based models with current published rates. They cover income tax, capital gains, and wealth tax where applicable. However, they are simplified approximations — they do not account for every deduction, credit, treaty provision, or subnational variation. The simulation shows directionally accurate results for mainstream resident-retiree cases. For precise tax planning, consult a tax professional.
No. Retirement Lab is a financial calculator. All results are hypothetical projections based on your inputs and assumptions — they are not recommendations, guarantees, or personalized advice. The simulation shows possible outcomes given the parameters you choose. Consult a qualified professional before making decisions about your retirement.
The full simulation engine — Monte Carlo runs, tax modeling, sensitivity analysis, and 2-country comparison — is free for everyone. Guests use it anonymously. Members have a free signed-in account and can save scenarios, share results, and run up to 10 simulations per day. Pro removes that daily run limit and adds capabilities: multi-country sweep across 3+ countries, custom portfolio allocation, withdrawal strategies, precision tax inputs, PDF export, and more. The same Pro capabilities are available with a 30-day Pro pass ($30, a one-time purchase with no auto-renewal), a monthly subscription ($10/month), or a yearly subscription ($80/year).
Guest session data is stored securely and retained for 7 days — your scenarios survive page refreshes during that period. After 7 days of inactivity the session and its data are automatically deleted. For signed-in users, scenarios are stored indefinitely and are only accessible to you. We do not sell, share, or use your financial data for any purpose other than running your simulations. Shared scenario links are revocable at any time. See our Privacy Policy for full details.
Yes. The Retirement Lab app in ChatGPT runs the same Monte Carlo simulations and tax modeling as this website. Describe your situation in plain language and ChatGPT asks Retirement Lab to run a hypothetical projection based on your inputs. Connecting needs a free Retirement Lab account, and results are saved to that account so you can open them here later. See the ChatGPT setup page for installation steps.