2027 tax brackets: not yet published, but 11 of 12 inputs are in

The federal income tax brackets for 2027 do not exist yet. As of October 20, 2026 the IRS newsroom listed releases through October 16, 2026, and none of them was the annual inflation-adjustment notice. The most recent entry on the agency's “inflation-adjusted tax items by tax year” page was still tax year 2026, published on October 9, 2025.

What does exist is the formula. Section 1(f) of the Internal Revenue Code says which price index moves the brackets, which twelve months count, and how the result is rounded. Eleven of the twelve monthly figures that feed the 2027 adjustment have been published by the Bureau of Labor Statistics. The twelfth, October 2025, never will be.

The 2026 brackets, the baseline the 2027 figures move from

That split is not a rounding accident. It is written into the statute, and it matters for 2027 too.

How the brackets are set: a chained-CPI ratio, two base years, rounded down

The index is the point of the exercise. BLS's explainer says the chained CPI “employs a formula that reflects the effect of substitution” across item categories, where the ordinary CPI-U “assumes consumers do not substitute across item categories”. When pork rises and beef does not, shoppers buy more beef, and the chained index “would rise, but not by as much as an index that was based on fixed purchase patterns”. BLS puts the December-to-December gap between the two at about 0.2 percentage points a year on average from 2001 to 2023. For the twelve months to September 2026 the CPI-U rose 3.7% and the C-CPI-U 3.5%, per the BLS release of October 14, 2026. The gap compounds: brackets indexed to the slower measure sit lower, relative to wages, than they would under the CPI-U. How the CPI is assembled is covered in the site's piece on CPI construction.

The inputs so far: 11 published months, one missing month, and a 3.2% rise

For comparison, the 2026 adjustment moved the upper thresholds 2.3% and the low ones 4.0%. The 2016 and 2017 bases are both fixed in the statute, so from 2027 the 10% and 12% brackets move by the same annual ratio as everything else, from the higher level the extra base year gave them.

What it means for your money

The bracket a household is “in” is its marginal rate: the tax on the next dollar. The effective rate is total tax divided by income, and it is always lower, because the first slices of income are taxed at 10% and 12% no matter how high the total goes. Indexing changes the width of those slices.

• A raise is taxed at the margin. For the couple above, a $1,000 raise that keeps taxable income under $100,800 costs $120 in federal income tax; a $1,000 raise that lands entirely above it costs $220. The tax on the first $100,800 does not change.
• Indexing is what stops inflation from doing the raising. If pay rose 3.5% and the thresholds did not move, more of the same real income would be taxed at 22%. The price data behind the adjustment are the same figures covered in the site's September CPI piece, applied with a lag.
• The standard deduction is indexed too. The 2026 joint deduction of $32,200 means the first $32,200 of a couple's income is taxed at 0%; add the $24,800 bracket and the first $57,000 of wages faces at most 10%.

Readers working out the room under a bracket edge can find that arithmetic in the Roth conversion piece; the separate schedule for long-term gains is in the capital gains piece.

When the number lands

Section 1(f)(1) requires the tables “not later than December 15” of each year. The release has come earlier: November 9, 2023 for tax year 2024, October 22, 2024 for tax year 2025, and October 9, 2025 for tax year 2026. It arrives as a Revenue Procedure with a news release on the IRS newsroom, and the figures apply to income earned in calendar 2027 and to returns filed in 2028.