2027 federal tax brackets: projected figures and how they are set

The IRS has not published the 2027 federal tax brackets yet. As of October 7, 2026, its newest inflation guidance is still Revenue Procedure 2025-32, which covers tax year 2026. The inflation data the law uses for 2027 is now published, though, and running the statutory formula on it gives a 2027 standard deduction of $16,600 for single filers, $33,200 for married couples filing jointly and $24,950 for heads of household, with every bracket threshold about 3.2% higher than in 2026.

One gap keeps this a projection. The Bureau of Labor Statistics never collected October 2025 prices because of the government shutdown, so one of the twelve monthly values the formula needs does not exist. The IRS has not said how it will handle that. Both reasonable methods are shown below, and they differ by $0 to $1,000 per threshold.

Projected 2027 brackets for single filers

Taxable income is income after the standard deduction or itemized deductions. Each rate applies only to the slice of taxable income inside its band.

Married filing jointly and head of household

Every joint threshold is exactly double the single one except the start of the 37% band: $793,650 joint against $661,375 single, not $1,322,750. In the bracket table, that is the only place a two-earner couple can pay more married than single.

Standard deduction and other 2027 amounts

For most filers the standard deduction matters more than the brackets, because it decides how much income is taxed at all, and a bigger one raises the bar for itemizing. Some 2027 amounts are already settled by statute or by the IRS; the rest come from the same formula as the brackets.

The fixed rows come from 26 U.S.C. section 151(d)(5)(C) (senior deduction), section 164(b)(7) (SALT cap), section 24(i) (child credit indexing, rounded down to $100), and IRS Revenue Procedures 2026-24 and 2025-19 (HSA limits).

The missing October, and what it changes

The statute averages 12 monthly values of the chained CPI, September 2025 through August 2026. BLS says in its shutdown FAQ that for most CPI series, October 2025 indexes were not published, and it computes its own 2025 annual averages from the 11 months that exist. There are two sensible ways to fill the hole:

• Average the 11 published months. This matches how BLS handles its own annual averages, and it produces the tables above.
• Fill October with the midpoint of September (180.373) and November (179.889), then average 12 months. This gives a slightly lower average.

The single and joint standard deductions, the extra 65+ amounts and the child tax credit come out the same either way, so those are the firmest numbers on this page. Bracket thresholds could land a little lower than the main table.

How the 2027 numbers are set

The rules are in 26 U.S.C. section 1(f) and 1(j), with the standard deduction in section 63(c)(7):

• Index: the chained CPI for all urban consumers (C-CPI-U), averaged over the 12 months ending August 31, 2026, using the values BLS showed on the day it published the first August figure. That day was September 11, 2026.
• Base years: each threshold starts from the amount written in the statute and grows by the ratio of the 2026 average to a base-year average. The top of the 10% and 12% bands uses 2016. Every higher threshold uses 2017. The standard deduction starts from $15,750 single and $23,625 head of household, indexed from 2024.
• Rounding: each figure is rounded down to a multiple of $50, or $25 for single filers' brackets. That is why single thresholds such as $52,025 end in 25.

We tested the method on the official 2026 tables. A 12-month chained CPI average of 177.11 reproduces all 18 official 2026 thresholds for single, joint and head-of-household filers. BLS now shows 177.21 for that window because it revises the chained CPI three times after first release, with final values 10 to 12 months later, per its chained CPI questions and answers. The 2027 inputs are the September 11, 2026 values, which is what the statute specifies, so later revisions do not move them.

How big the 2027 adjustment is

The 12-month chained CPI average used for 2027 is 3.19% above the prior window on today's BLS figures, and every projected bracket threshold is 3.2% above its official 2026 value. Monthly readings peaked in spring 2026:

For scale, here is how far one threshold, the start of the single 24% band, has moved each year in the official tables:

The statute lags by about a year. The 7.1% jump for 2023 came from 2022 prices, and prices from September 2025 through August 2026 set the brackets for income earned in 2027.

What it means in dollars

If your income stays flat, indexing cuts your federal income tax a little. These figures assume wages only, the standard deduction, and no credits:

Indexing is not a tax cut in real terms. A single filer earning $75,000 in 2026 pays an effective rate of 10.23%. Give that person a 3.2% raise to $77,400 in 2027 and the projected tax is $7,917.50, an effective rate of 10.23% again. If your pay rises more slowly than the index, your tax falls a little. If it rises faster, your effective rate creeps up. To see how many dollars you can add before reaching the next band, use the tax bracket headroom tool, and for how the bands apply to your income, read how federal tax brackets work.

When the official numbers arrive

The legal deadline is December 15: section 1(f)(1) requires the Treasury to prescribe the next year's tables by then. Expect the 2027 release in October or November 2026.

What to do with a projection

• Timing income you control. If a bonus, an invoice or a Roth conversion can land in December or January, the projected thresholds tell you roughly where the bands sit. Being off by up to $1,000 rarely changes that decision.
• Withholding. Your 2027 paychecks will use IRS withholding tables built on the official figures. If your pay is flat, expect slightly less federal tax withheld in January. See how your W-4 sets withholding.

Frequently asked questions

Sources

1. Revenue Procedure 2025-32 (2026 inflation-adjusted items), Internal Revenue Service. Checked October 2026.
2. IRS releases tax inflation adjustments for tax year 2026 (IR-2025-103), Internal Revenue Service. Checked October 2026.
3. 26 U.S. Code section 1, Tax imposed, Legal Information Institute, Cornell Law School. Checked October 2026.
4. 26 U.S. Code section 63, Taxable income defined, Legal Information Institute, Cornell Law School. Checked October 2026.
5. Chained CPI for All Urban Consumers, series SUUR0000SA0, U.S. Bureau of Labor Statistics. Checked October 2026.
6. 2025 federal government shutdown impact on the Consumer Price Index, U.S. Bureau of Labor Statistics. Checked October 2026.
7. Consumer Price Index, August 2026 news release, U.S. Bureau of Labor Statistics. Checked October 2026.
8. Revenue Procedure 2026-24 (2027 HSA limits), Internal Revenue Service. Checked October 2026.