2027 vs 2026: what changed in the retirement tax numbers

Around this time every year the 2027 numbers arrive one agency at a time, over three months, in four different documents — and most of what people repeat in between is a mixture of announced figures, projections and numbers that simply have not moved. This dataset separates them. One row per constant, 2026 beside 2027, and a status column that says plainly which of the four kinds each 2027 figure is.

How to read the status column

• OFFICIAL — the responsible agency has published the 2027 figure. Two families are already here: the ACA applicable-percentage table (IRS Rev. Proc. 2026-26) and the federal poverty level boundaries that govern 2027 marketplace coverage (91 FR 1797). The statutory top IRMAA floors sit here too, because the statute sets them rather than indexing them.
• PROJECTED — QuantCalc's own projection under the statutory indexing formula, because the agency has not published anything. Read these as estimates with a stated band, not as numbers to file or appeal on.
• UNCHANGED — 2027 equals 2026 as a matter of regulation or statute. Nothing is being forecast: the RMD divisors come from a regulation that is replaced only by a new Treasury rule, and the OBBBA senior deduction is set in nominal dollars through 2028.
• NOT YET ANNOUNCED — no 2027 figure exists yet, from anyone. Rather than carry a 2026 number forward and let it read as 2027 guidance, these rows say so.

The families at a glance

Federal ordinary-income brackets

Each row is a bracket ceiling — the income at which the next rate takes over. The 2027 column grows the official 2026 amount by the central chained-CPI case of +3.0% and rounds down to the next lowest multiple of $50, or $25 on the married-filing-separately schedule, per IRC §1(f)(7). The seven-rate structure itself is settled: OBBBA §70101 made it permanent, so only the dollar thresholds are open.

Standard deduction and the age-65 addition

The age-65 addition under IRC §63(f) is where the rounding rule shows its teeth: the unmarried amount steps up a notch while the per-married-filer amount does not move at all at the central case.

Long-term capital-gains breakpoints

The 0%/15%/20% breakpoints are indexed under IRC §1(j)(5)(C) using the same §1(f)(3) cost-of-living adjustment as the ordinary brackets, with the increase rounded down to the next lowest multiple of $50 and no separate married-filing-separately step. This is the one projected family with no 2027 reference page of its own on this site: the figures below apply the same growth factor this generator reads off the 2027 brackets page, so they move with it rather than independently of it.

RMD Uniform Lifetime Table

Nothing here moves. The Uniform Lifetime Table is prescribed by regulation — 26 CFR §1.401(a)(9)-9(c), adopted in T.D. 9930 and applicable to distribution calendar years beginning on or after January 1, 2022 — and is replaced only when Treasury issues a new rule with updated mortality assumptions. The same divisors applied in 2022 through 2026 and they apply in 2027. What changes about your RMD is your December 31 balance and your age, not the table. All 51 rows are in the CSV; the full divisor list is folded away below because every row of it says the same thing.

Medicare IRMAA MAGI bands

Two things to keep straight. First, the boundary rule: an interior tier applies only when MAGI exceeds its floor, so the next band opens one dollar higher — but the top floor is inclusive, which is why the last row reads “$500,000 and above”. Second, the top tier is not a projection at all: $500,000 single and $750,000 joint are held flat by statute through 2027 under 42 U.S.C. §1395r(i)(5)(C), with indexing resuming in 2028. The dollar surcharges are deliberately absent: they track Medicare programme spending rather than consumer prices and cannot be derived from CPI.

The same thresholds as numbers

ACA applicable percentage and poverty-level boundaries

This is the family that is already settled for 2027. The IRS published the 2027 applicable-percentage table in Rev. Proc. 2026-26; every band rose, and the ceiling crossed 10% for the first time. The dollar boundaries are settled too, for a reason that catches people out: under 26 CFR §1.36B-1(h) a coverage year runs on the poverty guidelines in effect on the first day of the preceding open enrollment period, so 2027 coverage runs on the January 2026 guidelines — already published. The cliff at 400% of FPL survives into 2027.

Social Security COLA

The COLA needs three CPI-W prints — July, August and September 2026 — and as of 2026-08-12 exactly one of them exists. That is why the row below carries a band rather than a point, and why the band narrowed when the July print landed on August 12, 2026.

Set by statute, and waiting

The OBBBA §70103 senior deduction is $6,000 per qualifying filer aged 65 or older with $75,000/$150,000 phase-out thresholds, all in nominal dollars with no inflation-adjustment clause anywhere in the subparagraph. It is identical in 2026, 2027 and 2028, and then it lapses — so 2027 is the second-to-last year it is available and its real value shrinks each year it survives.

The qualified-charitable-distribution caps and the quarterly estimated-tax underpayment rates are the rows with nothing to report yet. The QCD caps are indexed under SECURE 2.0 §307 and arrive in the IRS retirement-plan cost-of-living notice each autumn; this dataset does not project them. The §6621 underpayment rate is re-determined every calendar quarter in its own revenue ruling roughly a month ahead — even the fourth quarter of 2026 has not been set, let alone any 2027 quarter.

CC-BY-4.0 — free for any use including republication and journalism, with attribution to QuantCalc Research.

Methodology

Sources

2026 federal amounts

IRS Rev. Proc. 2025-32 (inflation adjustments for 2026), mirrored in QuantCalc's frozen tax engine. Revenue procedure PDF.

Indexing formulas for the projected rows

IRC §1(f)(3),(6),(7) (chained C-CPI-U, 12 months ending 31 August, increase rounded down to the next lowest multiple of $50, or $25 on the separate schedule) and IRC §1(j)(5)(C) (capital-gains breakpoints, same adjustment, $50 step). Statute text, retrieved 2026-08-12.

Medicare IRMAA

42 U.S.C. §1395r(i)(5) for the CPI-U indexing rule and the nearest-$1,000 rounding; §1395r(i)(5)(C) for the $500,000/$750,000 statutory freeze through 2027. 2026 thresholds from the CMS announcement of November 14, 2025.

ACA applicable percentage

IRS Rev. Proc. 2026-26 §3.01 for 2027; IRS Rev. Proc. 2025-25 §3.01 for 2026. 2027 revenue procedure PDF.

Federal poverty guidelines

HHS, “Annual Update of the HHS Poverty Guidelines”: 91 FR 1797 (January 15, 2026), FR Doc. 2026-00755, governing 2027 coverage; and 90 FR 5917 (January 17, 2025), governing 2026 coverage. The one-year offset is set by 26 CFR §1.36B-1(h).

Social Security COLA

42 U.S.C. §415(i); BLS CPI-W series CWUR0000SA0; the 2026 COLA of 2.8% announced by SSA on October 24, 2025; the July 2026 print of 327.104 from the BLS Consumer Price Index news release of August 12, 2026.

RMD table

26 CFR §1.401(a)(9)-9(c) (Uniform Lifetime Table III), adopted by T.D. 9930, 85 FR 72472 (November 12, 2020). Start ages per SECURE 2.0 §107.

QCD caps and the senior deduction

IRS Notice 2025-67 for the 2026 QCD caps; OBBBA §70103, Pub. L. 119-21, adding IRC §151(d)(5), for the senior deduction.

Estimated-tax rates

IRC §6621; the quarterly revenue rulings named in each row.

Related

• The five 2027 reference pages in depth: 2027 federal tax brackets (projected), 2027 IRMAA brackets (projected), 2027 RMD Uniform Lifetime Table, 2027 ACA applicable-percentage table, 2027 Social Security COLA.
• All 2026 numbers on one printable page: the 2026 retirement tax cheat sheet.
• The underlying 2026 datasets: Federal Tax Brackets, Capital Gains Brackets, IRMAA Brackets, RMD Table, ACA Federal Poverty Level Thresholds.
• Run your own income through the current brackets year by year: the free tax-aware simulation.

Changelog

• v2027.1 (2026-08-12) — initial release. 151 rows across 11 constant families, 33 OFFICIAL / 57 PROJECTED / 55 UNCHANGED / 6 NOT YET ANNOUNCED, cross-checked against the five QuantCalc 2027 reference pages.

Dataset license: CC-BY-4.0. QuantCalc is an independent retirement-planning research project. Not affiliated with, endorsed by, or sponsored by any government agency, including the Internal Revenue Service, the Social Security Administration, the Centers for Medicare & Medicaid Services, or the U.S. Department of Health and Human Services. Not financial, tax, or legal advice.

@misc{quantcalc20272027vs2026keyretirementtaxnumberswhatcha,
  title  = {2027 vs 2026 Key Retirement Tax Numbers — What Changed},
  author = {{QuantCalc Research}},
  year   = {2027},
  url    = {https://quantcalc.app/data/2027-vs-2026-changes/},
  note   = {Accessed <date>}
}