TaxEstimateCalculator

TaxEstimateCalculator is a this-year tax planner for self-managing retirees. It answers two questions the long-term retirement planners don't:

• How much more ordinary income (or Roth conversion) can I take this year before it costs me more than I want?
• What do I actually owe in estimated tax this quarter, and how do I avoid an underpayment penalty?

Built for the audience that already knows the concepts (brackets, IRMAA, safe harbor, RMD) but doesn't want to do the arithmetic by hand.

HEADROOM
• Hero number: "You can convert up to $X and stay in the 22% bracket."
• Marginal-rate curve plotting the tax on your next dollar against additional conversion. Bracket transitions show as step-ups; SS-taxability and OBBBA-phaseout regions show as bumps above the nominal bracket rate.
• Labeled x-axis at every upcoming bracket edge so you can read exact dollar headroom directly from the chart.
• Cliff list: IRMAA tiers (with 2-year forward perspective — a 2026 conversion drives 2028 premiums), LTCG 0%/15% threshold, OBBBA senior-bonus phaseout end. Each shows distance in dollars and annual cost if crossed.

PAY (FEDERAL + STATE)
• Target / Paid / Left progress bar against the safe-harbor target (lesser of 90% of this year's tax, or 100%/110% of last year's tax).
• Quarter-by-quarter table showing target vs actual payments.
• Two strategy modes: Safe Harbor (the standard 4-quarter view) and Pay-as-you-Convert (a what-if calculator: enter a hypothetical conversion, see the additional federal tax to add to your next 1040-ES voucher).
• December-withholding suggestion: cover the whole year's shortfall by withholding from a year-end conversion or distribution.
• State tax: full computation for no-income-tax states (TX, FL, AK, NV, NH, SD, TN, WA, WY) and flat-rate states (PA, IL, CO, MI, IN, KY, UT, NC, MS, AZ, ID, GA, IA, MA), now modeling per-person, age-gated pension/retirement-income exclusions and government-vs-private pension treatment. Progressive states (CA, NY, NJ, etc.) get an information card with the top marginal rate and retirement-income treatment.

REQUIRED WITHDRAWAL (RMD)
• Computes the required amount from your pre-tax balances and birthdate using the IRS Uniform Lifetime Table.
• Handles the SECURE 2.0 age-73 / age-75 split (depending on birth year).
• Flags the double-RMD trap if you deferred your first RMD past April 1.
• Lets you record what you've already withdrawn and shows what's left.

PRINTABLE PDF REPORT
• Three-page report mirroring a CPA tax-planning analysis: income summary, bracket-fill tax calculation, federal + state summary, estimated quarterly payments, headroom analysis, source citations.
• Share to Files, Mail, AirDrop, or print directly.

DATA OWNERSHIP
• 100% on-device. No account, no sign-in.
• Zero analytics, tracking, or telemetry SDKs.
• No network requests from the engines or UI. The only network path is Apple StoreKit if you tip.
• Your household profile saves to a plain JSON file in the app's Documents directory.
• Export your data to share with your tax preparer or move to a new device. Import from any prior export.

REFERENCE
• Glossary explaining every term the app uses (Roth conversion, MAGI, IRMAA, safe harbor, OBBBA bonus, etc.).
• Reference Data hub you can drill into — federal brackets, capital gains, deductions, Social Security taxability, IRMAA tiers, the RMD table, and per-state pension exclusions — each with its source citation (IRS Rev. Proc., CMS, state DOR).
• State Tax screen with rate and retirement-income treatment for all 50 states + DC.

NOT TAX ADVICE
TaxEstimateCalculator is an estimator. It is not tax advice. Confirm any decision with a CPA, EA, or qualified tax preparer.

Supports all five filing statuses (MFJ, QSS, Single, HoH, MFS) and the 2026 tax year.