Every multi-year tax decision in retirement — Roth conversion sizing, withdrawal sequencing across taxable/pre-tax/Roth, IRMAA-tier management, RMD projections, capital gain harvesting — runs against the same input set: the current year's federal brackets, the standard deduction, the relevant contribution limits, and the IRMAA tier thresholds. When any one of those inputs is wrong or stale, the whole projection is wrong.

The IRS releases inflation-indexed amounts (brackets, standard deduction, IRA contribution limits, etc.) annually in a fall Rev. Proc. for the following tax year. Retirement plan limits (401(k), 403(b), 457, SIMPLE, SEP) are released in a separate annual Notice. CMS announces Medicare premiums and IRMAA tier thresholds each October. Each of those amounts can change year to year, and SECURE 2.0 introduced staged catch-up enhancements (the 60-63 super catch-up began in 2025) that make the catch-up rules genuinely complex.

Roth IRA income phaseout ranges are particularly easy to miss — they're tied to MAGI, not taxable income, and the inclusion of items like Roth conversion income in MAGI means a household making large conversions can phase out of direct Roth contributions even while doing the right strategic move. Knowing the exact 2026 thresholds is what lets the conversion-and-contribution combo work cleanly.

IRMAA tier thresholds for married filing jointly were frozen at $212K, $266K, $334K, $400K, and $750K through 2027 by legislation, so they don't index with inflation the way single-filer thresholds do. That means MFJ households doing aggressive Roth conversions need to plan against fixed dollar thresholds, not moving targets — a planning quirk most retirees and many advisors miss.

Use this reference as the input layer for every retirement-tax decision: when sizing this year's Roth conversion, when projecting next year's RMD, when calculating whether a capital gain harvest fits in the 0% federal LTCG bracket, when filing for IRMAA reconsideration after a life-changing event. Bookmark it, and check it again every January when prior-year tax filing closes and current-year planning opens.

Each table below cites the primary source. If a number changes after the verified-on date — usually because Congress passed legislation or CMS issued a revised announcement — verify against the source URL before relying on it for decisions worth tens of thousands of dollars.

For Arizona-specific amounts (the 2.5% flat state income tax, the Social Security state exemption, inherited IRA deduction phaseouts), see the Arizona Retirement Tax Guide linked in the cross-links section.

• Using last year's brackets or contribution limits because the spreadsheet was built in October. The IRS Rev. Proc. for the following year is published in October-November, and current-year planning should use the new amounts as soon as they're released.
• Confusing taxable income with MAGI when checking Roth IRA phaseout ranges, IRMAA thresholds, or healthcare premium tax credit eligibility. Each of those tests uses a slightly different version of MAGI.
• Treating the IRMAA MFJ thresholds as inflation-indexed. They're frozen by statute through 2027 — single-filer thresholds index, MFJ does not.
• Forgetting that the SECURE 2.0 60-63 super catch-up only applies to participants age 60 through 63 in the calendar year, and the underlying plan must offer it. Not all plans do.
• Using the IRS Uniform Lifetime Table when the original IRA owner had a spouse more than 10 years younger as the sole beneficiary — that case uses the Joint and Last Survivor Table instead.