Disclaimer & Terms

FEAsible is an educational and illustrative planning tool. It is not financial, tax, legal, accounting, or investment advice, and using it does not create an advisory or fiduciary relationship. It is not a recommendation to buy, sell, or hold any security or to adopt any strategy.

All outputs are hypothetical projections generated by Monte Carlo simulation from the assumptions you enter. They model many possible futures and report probabilities; they are not predictions and are not a guarantee of future results. A “confidence” figure is the share of simulated scenarios that succeed under your inputs — not the likelihood that your real-world plan will succeed.

Every effort has been made to root the calculations in current U.S. tax law and accepted financial principles. Even so, tax law changes, our interpretation may differ from your situation, and not every edge case, input combination, or interaction has been modeled or tested. The tool is provided “as is,” without warranties of any kind, and to the fullest extent permitted by law Engineered Finance accepts no liability for decisions made in reliance on it.

Always verify anything you intend to rely on, and consult a qualified financial, tax, or legal professional before making decisions.

Your data stays with you. FEAsible has no server-side accounts or storage — everything you enter lives in your browser session only. Save and load happens through files you download and keep; nothing is transmitted to or stored by us.

Assumptions & Limitations

To keep results understandable, FEAsible makes simplifying assumptions. Knowing where the model is thin helps you read the output well.

• Taxes (U.S.). Models federal plus a single state income tax, RMDs, Social Security taxation, and Medicare/IRMAA surcharges as a strong approximation of current law. Filing status is Single or Married Filing Jointly. Not every credit, phase-out, local tax, or future law change is captured — this is not tax-prep software.
• Markets. Returns are drawn from a multi-asset model using normal (bell-curve) distributions, which can understate the frequency of extreme “fat-tail” crashes and booms. You can set a fixed mix, a per-account mix, or an age-based glide path on the Investment Strategy page.
• Inflation. A single long-run average with modest year-to-year variability. It does not model sustained high-inflation regimes or shocks.
• Social Security estimate. The “estimate from income” helper is a simplified approximation using the 2026 benefit formula; it can run a few percent high for very high earners. Prefer your actual benefit estimate from ssa.gov when you have it.
• Projections are probabilistic. Results summarize thousands of simulated paths. Individual figures (success rate, ending wealth, goal funding) are statistics across those paths, not a forecast of your specific outcome.
• Current as of 2026. Tax brackets, contribution limits, and Social Security parameters reflect 2026 figures as we understand them and are reviewed periodically.

Changelog