Accuracy & Tax Data
How we make sure the numbers you see are current, source-backed, and honest about their limits.
RetireSmartIRA is a retirement-planning tool, not tax-preparation software. Its job is to give you a clear, year-by-year picture of how withdrawals, Roth conversions, and Social Security timing affect your federal and state taxes — so you can compare decisions before you act. For that to be useful, the underlying tax data has to be current and traceable to official sources. Here's how we make sure it is.
Where the numbers come from
Federal
Tax parameters come from official IRS guidance for the current planning tax year — the annual IRS Revenue Procedure that sets inflation-adjusted brackets, the standard deduction, and contribution limits, plus any signed legislation in effect for that year (for example, the One Big Beautiful Bill Act senior bonus deduction).
State
All 50 states plus DC are modeled. When a state changes its tax law, we verify the change against primary sources — the state's department of revenue, official rate schedules and forms, and enacted legislation. Secondary summaries are used only as a sanity cross-check, never as the basis for a change. As of version 2.5, every state shows the date it was last verified and the sources used, inside the app, so you can check the provenance of any number without taking our word for it.
How changes are verified
Every materially changed state goes through primary-source verification plus automated regression testing and an independent review of the change against the cited official source. We check changed states against specific primary-source documents — forms, schedules, statutes — not general tax-summary pages that may quietly reflect a different tax year.
The app's tax engine is backed by 3,200+ automated tests that re-check the math on every release, so a correct number stays correct. The free Roth conversion calculator on this site is checked the same way — see every case on its verification page.
What this app doesn't cover
These are deliberate scope choices — RetireSmartIRA is built to be the best tool for retirement-decision planning, not a general-purpose tax calculator.
Local and city income taxes
Built-in city tax schedules are not modeled: the app does not know NYC's or Yonkers' own brackets. You can enter a flat local rate in Settings, which is applied to your state-adjusted income as an approximation.
Filing status
The app models Single and Married Filing Jointly — the two statuses most relevant to retirement planning. Married Filing Separately and Head of Household are not separately modeled.
Certain state surtaxes and retirement-income phaseouts
Phaseouts are modeled per state, with stepped bands where the state uses them. Where a state's rule is simplified, that simplification is disclosed on that state's own page in the app.
Estate, gift, and inheritance taxes
Out of scope — this is a retirement-planning tool, not an estate-planning tool.
General tax credits
Credits not typically relevant at or near retirement (EITC, child tax credit, and similar) are not modeled.
Kept current
We refresh state and federal tax data at least once per tax year, and fold in mid-year state changes through maintenance releases when they're material. The app version is bumped on every release that touches tax data, so you can always confirm you're on a current build.
After our latest verification pass (v2.6.0), we are not aware of any materially wrong state rate structure within the app's supported filing statuses and retirement-planning use. As always, RetireSmartIRA produces estimates for planning — please consult a qualified tax professional or financial advisor before making financial decisions.
Want the full detail?
Our complete Tax Data Methodology — including the per-state verification process, source hierarchy, and release-by-release inventory — is available for press and professional review.
Stop guessing. Start planning.
Updated for 2026 IRS limits, HHS poverty guidelines, ACA cliff thresholds, and all 50 state tax brackets. Free to download.