Datasets
State Retirement Tax Data 2026
Downloadable CSV/JSON dataset of per-state 2026 retirement-tax policy facts — top marginal rate, standard deduction, Social Security taxability, qualified-retirement-income exemptions, and Roth-conversion treatment for all 51 U.S. jurisdictions, generated directly from QuantCalc's frozen state-tax engine.
RMD Table 2026
Downloadable CSV/JSON dataset of the 2026 IRS Uniform Lifetime Table III used to calculate Required Minimum Distributions (RMDs) — distribution period factor and RMD percentage of balance for every age 72-120, plus the SECURE 2.0 RMD start-age table by birth year, generated directly from QuantCalc's canonical tax-constants mirror.
IRMAA Brackets 2026
Downloadable CSV/JSON dataset of the 2026 Medicare IRMAA brackets — per-tier MAGI thresholds (single and married filing jointly) with monthly and annual Part B and Part D surcharges, generated directly from QuantCalc's canonical tax-constants mirror.
Federal Tax Brackets 2026
Downloadable CSV/JSON dataset of the 2026 federal ordinary-income tax brackets for all 4 filing statuses (single, MFJ, MFS, HOH), plus the standard deduction, the additional standard deduction for filers 65+, and the OBBBA senior deduction parameters, generated directly from QuantCalc's canonical tax-constants mirror.
Capital Gains Brackets 2026
Downloadable CSV/JSON dataset of the 2026 federal long-term capital-gains tax brackets (0%/15%/20%) for all 4 filing statuses, plus the §1411 Net Investment Income Tax (NIIT) threshold and rate, with an illustrative tax-on-$10,000-gain column computed via QuantCalc's production capital-gains tax function.
State Social Security Tax 2026
Downloadable CSV/JSON dataset of how all 51 U.S. jurisdictions tax Social Security benefits in 2026 — which 8 states tax some SS, the exact AGI exemption thresholds (single and MFJ) each uses, and a plain-language description of each state's statutory rule, generated directly from QuantCalc's frozen state-tax engine.
ACA Federal Poverty Level Thresholds 2026
Downloadable CSV/JSON dataset of the 2026 ACA Federal Poverty Level thresholds: the FPL for household sizes 1-8, the computed 100% / 138% / 250% / 400% MAGI thresholds that drive Medicaid eligibility and marketplace premium subsidies, the current-law 2026 applicable-percentage schedule (2.10%-9.96%, with the restored 400% FPL cliff), and the Medicaid-expansion status list.
Sequence-of-Returns Risk by Retirement Cohort 2026
Downloadable CSV/JSON dataset: for every U.S. retirement start year 1871-1993 with a full 30-year window, the realised first-5-year and first-10-year annualized real return and the 4% rule terminal outcome on a 60/40 portfolio. One headline number distils it: the Spearman rank correlation between the first five years and the 30-year outcome is 0.633. Historical, computed, CC-BY-4.0.
Machine-readable index
Every dataset above, listed in one file (URL, title, version, last-updated date) so you don't have to scrape this page to find them.
Methodology
About these datasets: Every figure on every dataset page linked above is generated directly from QuantCalc's production tax engine or its canonical client-side tax-constants mirror — not hand-transcribed into HTML from a statute, IRS table, or CMS notice. Each dataset's own page documents its specific source function and scope in its Methodology section.
Consistency: The C engine and its JavaScript port are checked against each other by an exhaustive JS↔C parity test suite, so a dataset page, the interactive calculator, and the backend all report the same figures.
This index: Generated by scripts/gen_data_hub.mjs, which reads each dataset's own index.html head (title, description, canonical URL) and JSON envelope (version, generated date) rather than duplicating any tax figure. Re-running it against the same dataset pages reproduces byte-identical output.
Not tax advice: These are reference datasets for research and planning purposes, not a substitute for professional tax advice.
Turn this data into a plan
These datasets show the rules. The Roth Conversion Planner applies them to your own numbers — state tax, RMDs, and IRMAA cliffs included — to build a year-by-year conversion schedule.
Plan your Roth conversions →Looking for the research behind these numbers instead of the raw data? See the Research index.