Known limits

9to95 is a calculator. It runs arithmetic on the figures you give it and reports numbers. Every result is hypothetical, and a model that leaves something out can be wrong in either direction.

Taxes

• One tax-law year, carried forward. The tax tables are written for 2026. Later years are the 2026 figures scaled by the assumed inflation rate. The calculator does not predict changes in tax law, and it does not know about rules that take effect after the tables were written.
• Some state tables are only partly confirmed. Each state table carries a status: confirmed against an official source, confirmed in part, or not yet re-checked against current law. Results for a state that is not fully confirmed are weaker than results for one that is.
• Married filing separately is not covered at all. Married filing jointly and single are covered end to end. Head of household is covered for federal tax, with an approximation for state tax in states that have no specific figures for it.
• Tax figures are planning estimates. They are not a tax return and are not built to prepare or check one.
• Local taxes are a short list. Only a handful of city, county and school-district taxes are included. In Ohio, for example, two of the 214 school districts that levy an income tax are included, so a household in any other district is shown no district tax.
• Some state rules are deliberately left out. Examples: city wage taxes; different state treatment of federal civil-service pensions (CSRS and FERS); states that tax Roth conversions differently from the federal rules; states that tax qualified dividends differently from the federal rules; state rules for 529 plans in other states and for rolling 529 money into a Roth account; state rules for life-insurance and annuity payouts; senior property-tax assessment freezes; and income-based property-tax credits (circuit breakers). Many of these cannot reach a typical retirement household, but some can change a state tax bill.
• One state at a time. A move to another state takes effect for the whole household at once. A move partway through a year, income split between two states, and tax owed to a former state are not modeled.
• Charitable giving is not modeled for tax effect. The calculator does not model bunching gifts into one year or donor-advised funds, and a setting for them changes nothing in the results. State rules that reward charitable gifts to someone who does not itemize, such as Arizona's, are not included. Planned giving can be entered as an expense.

Estate and gifts

• State estate tax is calculated for New York only. Eleven other states and Washington, DC levy their own estate tax: Connecticut, Hawaii, Illinois, Maine, Maryland, Massachusetts, Minnesota, Oregon, Rhode Island, Vermont, Washington, and DC. For a household that lives in one of them, the calculator leaves the state estate tax out and says so, and the estate total shown is federal tax only. That total is not the real bill.
• Inheritance taxes and state gift taxes are not modeled. Several states tax what an heir receives, depending on the heir's relationship to the person who died. Connecticut also counts gifts made during life against its estate tax exclusion. None of this is in the results.
• Federal and New York figures use one year of law. The federal exclusion is the 2026 figure, rising with inflation afterwards. The calculator does not predict changes to it.
• Advanced trusts are not modeled. Grantor retained annuity trusts, spousal access trusts, intentionally defective grantor trusts and charitable remainder trusts depend on terms fixed in a legal document on a particular day, so they are left out.
• Passing wealth down stops at the first heirs. Wealth passed down more than one generation is not modeled. If a person who inherited an IRA dies before emptying it, the next heir's own ten-year deadline is not modeled.

Income and accounts

• Accounts are broad mixes, not products. Each account is described by the share held in stocks, bonds, cash and inflation-protected bonds. The calculator does not model individual securities or particular funds, and it cannot say how any one of them would behave.
• Incentive stock options are only partly modeled. The exercise is counted as an alternative minimum tax item, but the calculator does not track the shares you hold, the exercise cost, a later sale, or the separate cost basis used for that tax.
• Section 83(b) elections for restricted stock are not modeled.
• Like-kind property exchanges (Section 1031) are not modeled.
• Variable annuities are not modeled while they are still growing.
• Inputs come from you. The calculator does not check your figures against your bank or brokerage. A wrong input gives a wrong result.

Monte Carlo and markets

• What varies. Each simulated trial draws returns for stocks, bonds and cash from the historical record for 1928 to 2024, together with inflation, healthcare cost growth, unplanned expenses (a long-term-care event, a home repair, a smaller emergency) and, in one of the two readings, how long each person lives.
• What stays fixed in every trial. Tax law and benefit formulas do not change from trial to trial. The assumed real yield on inflation-protected bonds is a fixed figure. Home and rental property values grow at a steady assumed rate, so real estate prices are not simulated.
• History is not the future. The market draws come from past years only. A future that differs from every past year, in either direction, is outside what the simulation can show.
• Two readings, two questions. One reading assumes a fixed planning age. The other samples lifespans from Social Security mortality tables. They answer different questions, so their probabilities differ, and neither describes your own lifespan.
• Results move with the seed and the trial count. A probability of success from 500 trials is a point estimate. A different seed or a different number of trials gives a slightly different number.
• Only spendable money counts. Running out of money is judged on investable accounts. Home equity is not counted as spendable.

What the calculator never does

• It gives no advice. The output is educational modeling based on the inputs you provide. It is not financial, investment, tax, legal, accounting or insurance advice.
• It makes no recommendation. It does not recommend any security, fund, product, provider or mix of stocks, bonds and cash, and it does not tell you what to buy, sell or hold.
• It does not choose for you. It shows the plans you define side by side. Where you ask, it can also run a range of options that you set, such as claim ages, retirement ages, spending levels or conversion amounts, and show the result for each one on a measure that you pick. That is arithmetic on a model, not a judgment that an option is right for you. Which one fits your life depends on things the model cannot see, and the choice is yours.
• It does not speak for your assistant. Anything your AI assistant adds to the numbers comes from the assistant, not from 9to95.

Before you make a financial, tax or legal decision, consider speaking with a licensed professional who can look at your whole situation. To report an error, or a limit missing from this page, write to support@9to95.com.