The legislature just passed a plan to phase out Missouri's income tax by 2032 and replace it with an expanded sales tax. Sounds like a tax cut — for most people it isn't. Type in your income below.
Source: Missouri Budget Project / Institute on Taxation and Economic Policy (ITEP). Moderate scenario.
A1 — Only the standard deduction is modeled. No itemized deductions, no tax credits. Most Missourians take the standard deduction, so this is a reasonable baseline. If you itemize heavily (mortgage interest, business deductions), your actual income tax savings from the swap would be smaller — meaning the swap hurts you more than shown.
A2 — Retired filers assumed 85% Social Security, 15% other taxable income. Missouri exempts SS entirely. This reflects the average MO retiree on fixed income. Retirees with significant pension or 401(k) income have higher taxable income and would see larger income tax savings from the swap.
A3 — No growth effects modeled. This calculator shows the direct impact only — it does not assume the swap attracts new businesses or residents that expand the tax base. That's the core pro-swap argument (Laffer Curve) and it's genuinely contested. Kansas tried it in 2012; their legislature reversed it by 2017. Missouri is more exposed than Kansas was.
A4 — Spending as % of income tapers with income. Low-income households spend nearly everything; high-income households save more. ~92% at $20K, tapering to ~40% at $500K+. Based on BLS Consumer Expenditure Survey data, consistent with ITEP methodology.
A5 — Three scenarios, not one. The bill doesn't define the new sales tax rate or base — that's left to future legislators with no voter approval needed. Conservative (~10%, no base change), Moderate (~10%, base +35%), Aggressive (~12.5%, base +60%). ITEP's analysis says 12–15% would be needed if the base isn't expanded. Gov. Kehoe promised exemptions for healthcare, groceries, and real estate — none of that is in the bill.
A6 — "Added sales tax" = increase over today, not total sales tax paid. This isolates the cost of the swap. Your actual total sales tax bill would be higher than the delta shown.
A7 — Service cuts aren't modeled. There's a $5B+ estimated revenue gap. Cuts to Medicaid, schools, and social services have real costs — especially for lower-income households who depend on them. These could be larger than your direct tax impact.
A8 — St. Louis city and Kansas City earnings taxes aren't modeled. Both cities have a 1% local earnings tax. STL city residents' income tax "savings" from the state swap are partly eaten by this local tax that stays in place. The calculator overstates the benefit for STL and KC residents.
A9 — The crossover point is fragile. The ~$200–300K crossover where the swap turns green is sensitive to assumptions. Higher sales tax rates or broader base push it higher. Even high earners might not save under the aggressive scenario.