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How it works

How tax and Roth conversions are calculated

Federal and state tax, standard vs. itemized deductions, Roth conversion planning, RMDs, and IRMAA — this is an estimate to help you plan, not tax preparation.

Using the Estimate My Tax screen

This is a single current-year estimate, separate from the multi-year projection you get from "Run projections" — use it when you just want a quick answer for this year's taxes without filling in your whole retirement plan. If you're signed in with a saved profile, your state, filing status, dependents, marital details, and both people's dates of birth are prefilled automatically; everything else starts blank.

Fill in your (and your spouse's, if married) income and self-employment details, then the shared "Both" section below for household-level figures — interest, dividends, rental income, capital gains, and deductions — following the same order as the real Form 1040. Checking "self-employed" reveals a Solo 401(k) field; checking a rental's "Is it Qualified Business Income?" box auto-fills a 20% QBI deduction, which you can override by checking "Adjust this figure" next to it.

Add any properties you own under "Property," with their mortgages, so RetireWell can calculate your real mortgage-interest deduction instead of an approximation.

Click "Estimate tax" to see a simplified Form 1040 (federal) line-item breakdown, labeled with the real IRS line numbers, plus a state tax breakdown next to it — Form 540 with FTB line numbers if you're in California, a simplified generic breakdown for the 15 flat-tax states, or a one-line "no state income tax" note for the 9 no-tax states — and a further visual breakdown below. Use "Edit inputs and estimate again" to go back and adjust anything.

Federal income tax

RetireWell applies the real progressive federal tax brackets to your projected taxable income each year, using separate tables for Single and Married/Registered Domestic Partner (RDP) Filing Jointly. The bracket thresholds themselves grow with inflation each future year, the same way the real tax code adjusts them annually.

Standard vs. itemized deductions

Every year, RetireWell computes both your standard deduction and your itemized deduction, and uses whichever is larger — exactly like a real return.

  • Itemized deduction includes: state and local taxes (SALT), mortgage interest on a linked primary-residence loan, medical expenses above 7.5% of your income, and your charitable contributions (see the charitable-giving rules below).
  • Additional standard deduction at 65+: $2,050 for Single or Head of Household filers, or $1,650 per spouse age 65+ for married filers — these stack if both spouses qualify.
  • Additional standard deduction if legally blind: the same per-person amount as the age-65+ addition above, and it stacks with it — someone who is both 65+ and legally blind gets the addition twice.
  • Qualified Business Income (QBI) deduction: RetireWell auto-calculates 20% of any rental income you've marked as QBI-eligible as a separate deduction, applied whether or not you're self-employed — you can override the auto-calculated amount if you know your real figure.
Good to know: A separate temporary federal senior deduction (2025–2028, income-limited) can also apply on top of the amounts above — RetireWell applies it automatically when you qualify; you don't need to enter anything extra for it.

Charitable giving rules (2025 tax-law changes)

If you itemize, your cash charitable contributions are deductible up to 35% of your AGI (RetireWell deliberately uses a more conservative cap than the 60% the law technically allows), and only the portion of that capped amount above 0.5% of your AGI actually counts — a small "floor" that trims the very first slice of your giving.

If you take the standard deduction instead of itemizing, you still get a separate cash-gift deduction on top of it: up to $1,000 (Single, Married Filing Separately, or Head of Household) or $2,000 (Married/Registered Domestic Partner (RDP) Filing Jointly) — something the tax code didn't previously allow for non-itemizers.

Good to know: If you're in the top two federal brackets (35% or 37%), the tax value of your itemized charitable deduction is capped at 35 cents per dollar given, even though your bracket rate is higher — RetireWell applies this automatically.

State tax

What happens here depends on which state you selected. The 9 states with no income tax (Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, Wyoming) show $0 state tax and no further breakdown. For the 15 flat-tax states (Ohio, Arizona, Indiana, Louisiana, Pennsylvania, Iowa, North Carolina, Kentucky, Mississippi, Michigan, Colorado, Utah, Illinois, Georgia, Idaho), RetireWell applies that state's own flat rate to your income minus its own standard deduction — some of these states have no standard deduction at all, which is accurate for them, not a placeholder. No itemized-deduction modeling exists yet for these states.

California gets the most detailed treatment, described below — its own bracket table, its own standard/itemized deduction rules (California doesn't cap the SALT deduction the way federal does), a surtax, and a set of exemption credits none of the other modeled states have. Any state outside these 25 isn't modeled yet and also shows $0, as a known simplification — see the callout below.

California-only rules

  • CA Behavioral Health Services Tax: a flat 1% surcharge on California taxable income above $1,000,000 — only the excess above that line is taxed at 1%, not your whole income, and the threshold does not double for joint filers.
  • CA exemption credits: subtracted directly from your California tax, not your income: $153 for yourself ($306 if Married/Registered Domestic Partner (RDP) Filing Jointly), $475 per dependent, $153 per person age 65+, and $153 per person legally blind. These can all stack.
  • Credit phase-out: if your federal adjusted gross income crosses a threshold ($252,203 Single/Married Filing Separately, $378,310 Head of Household, $504,411 Married/Registered Domestic Partner (RDP) Filing Jointly), these credits shrink by $12 for every $2,500 you're over, until they reach zero.

How much of your Social Security is taxable

RetireWell applies the real three-tier "combined income" test the IRS uses (your other income plus half your Social Security benefit), rather than assuming a flat percentage — depending on your total combined income, anywhere from 0% to 85% of your benefit ends up taxable.

Other taxes that can apply

  • Net Investment Income Tax (NIIT): a federal 3.8% surtax on investment income above $250,000 (married) or $200,000 (single) — despite the name it appears under in some exports, this is a federal tax, not a California one.
  • Additional Medicare Tax: a federal 0.9% surtax on wages or self-employment income above your filing-status threshold.
  • Self-employment tax: if you've marked yourself (or your spouse) self-employed, RetireWell calculates the real Social Security and Medicare self-employment tax on that income (Schedule SE), and lets half of it reduce your taxable income the same way a real return does.

401(k), HSA, and student loan interest

Traditional 401(k) and HSA contributions reduce your taxable income for the year they're made; Roth and after-tax 401(k) contributions don't, since that money has already been taxed. If you haven't entered real contribution elections, RetireWell falls back to a rough estimate for higher earners rather than assuming everyone maxes out.

Interest on a loan tagged as a student loan is deductible up to $2,500/year, phasing out at higher income — and if a student loan's payoff date lands after your planned retirement age, RetireWell flags that as something worth reconsidering.

Roth conversion strategy

For each year before Required Minimum Distributions begin, RetireWell looks for room to convert traditional retirement savings to Roth without pushing you past the top of the 22% federal bracket — a widely-used rule of thumb, since 22% is a historically moderate bracket to pay conversion tax at. For married households, both spouses' income and conversion room are considered together.

Converting itself is never penalized, no matter your age — but if RetireWell recommends converting before you turn 59½, be aware of two separate 5-year rules that apply if you then withdraw that money early: each conversion starts its own 5-year clock on withdrawing the converted principal penalty-free, and there's a separate 5-year-and-59½ rule for withdrawing the account's earnings tax-free.

Required Minimum Distributions (RMDs)

Your RMD start age is set by your birth year, per the SECURE 2.0 Act — 73 for most people currently approaching retirement, moving to 75 for people born in 1960 or later. Once RMDs begin, RetireWell calculates the required withdrawal each year using the IRS Uniform Lifetime Table, and compares that path against your Roth-conversion plan so you can see the tax difference between the two.

Medicare IRMAA surcharges

Once either spouse turns 65, RetireWell checks your income against Medicare's income-related monthly adjustment (IRMAA) tiers — Medicare actually looks back two years at your income to set this, so RetireWell mirrors that same two-year lookback rather than using your current-year figure directly.

What this isn't

Not tax advice: This is a planning estimate, not tax preparation. It doesn't account for every possible credit or situation, and state tax is only modeled for California, the 9 no-income-tax states, and 15 flat-tax states — any other state shows $0 as a known simplification — talk to a licensed tax professional before making a real financial decision based on it.

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