The simple version

A set of tax figures carries a year in its name, and that year is the one it applies to. Not the year you are sitting in when you read about it.

So a set published for a coming year does not touch the return in front of you. That return runs on the set published a year earlier, which is already fixed and already in use.

The agency does not leave this to be worked out. Both of the releases read here write the filing year in, one line under the opening figures.

The numbers

• The Internal Revenue Service announced the tax year 2027 inflation adjustments on November 5, 2026, in news release IR-2026-133, with the detail in Revenue Procedure 2026-35.
• The release covers almost 70 tax provisions, and states that the tax year 2027 adjustments generally apply to tax returns filed in 2028.
• Standard deduction for tax year 2027: $33,200 for married couples filing jointly, up $1,000 from 2026; $16,600 for single filers and for married individuals filing separately; $24,925 for heads of households.
• Rate thresholds for tax year 2027: the top rate stays 37% for single filers with income above $661,375 and married couples filing jointly above $793,650. Below that come 35% above $264,550 ($529,100 jointly), 32% above $208,325 ($416,650), 24% above $109,125 ($218,250), 22% above $52,025 ($104,050), and 12% above $12,800 ($25,600).
• The lowest rate is 10%, for single filers with income of $12,800 or less and married couples filing jointly at $25,600 or less.
• The maximum child tax credit for 2027 is $2,300, up $100 from 2026, and the refundable portion is $1,800, also up $100.
• The prior year's release shows the same pattern. The IRS announced the tax year 2026 adjustments on October 9, 2025, in IR-2025-103, with the detail in Revenue Procedure 2025-32.
• That release states that the tax year 2026 adjustments generally apply to tax returns filed in 2027. Same sentence, same position, one year apart.
• Standard deduction for tax year 2026: $32,200 for married couples filing jointly, $16,100 for single filers and for married individuals filing separately, $24,150 for heads of households.
• The year-over-year gap by filing status: $1,000 for married couples filing jointly, $500 for single filers and for married individuals filing separately, $775 for heads of households. Those three differences are ours, worked from the two releases.
• Both sets were published before the year they cover had begun: the 2027 figures 57 days before, and the 2026 figures 84 days before. Those two day counts are ours, worked from the release dates.

Why the figures arrive before the year they cover

The timing looks strange until you notice when money first changes hands. Paychecks start in January, and an amount comes out of each one from the first.

Working that amount out needs the figures for the year the pay belongs to. If those landed at filing time instead, every employer would run a whole year on an approximation and fix it afterwards. That explanation is ours: neither release gives a reason for the timing.

So they are settled before the year opens. A release landing in front of you is not early news about a change. It is the paperwork that has to exist before January can happen at all.

The actual math on reaching for the wrong set

Put the two sets side by side and the cost of mixing them up is easy to see. On the largest of the flat amounts, the later year reads $33,200 against $32,200 for the year before it, a gap of $1,000.

Claim the higher one on the earlier return and you have claimed $1,000 you were not owed. At a 22% rate, a rate both years carry, that is $220 of tax.

The 22% is a stated assumption rather than anyone's actual rate, and the gap is a different size on each of the other lines, running from $500 to $775. What holds every time is the direction. Reaching forward a year always overstates.

What this means

When a new set lands, the question worth asking is which return it belongs to, and the release answers it in a line most coverage skips over.

It also explains why the coverage can feel like news about something that already happened to you. The figures are real and settled. The year they belong to has not started.

What this is NOT

This article explains which tax year and which filing year a published set of IRS figures applies to, using the tax year 2027 adjustments in IR-2026-133 and the tax year 2026 adjustments in IR-2025-103 as its worked example, both read on November 10, 2026. It is not tax advice and not guidance on filing, planning, withholding, deductions, credits, or any tax decision, all of which depend on individual circumstances and belong with a credentialed professional. It does not tell you which figures apply to your own return, because that turns on your tax year, your filing status and facts this article cannot see. The $1,000, $500 and $775 gaps and the $220 figure are ours, worked from the two releases, and the 22% rate in that example is a stated assumption, not a lookup of anyone's rate. The two day counts, 57 and 84, are also ours, worked from the release dates. It is not a claim that every figure in either release moved, that the pattern holds for state taxes, or that an adjustment can never be changed by later legislation. Both source releases carry the naming and framing their publisher chose, and quoting a figure from a release is not an endorsement of that framing. This is not a political endorsement or criticism of anyone.

Sources

• Internal Revenue Service, news release IR-2026-133, tax year 2027 inflation adjustments, November 5, 2026, read November 10, 2026, for the filing-year sentence, the standard deduction amounts, the rate thresholds and the child tax credit figures.
• Internal Revenue Service, Revenue Procedure 2026-35, the underlying document for the tax year 2027 adjustments, cited by that release.
• Internal Revenue Service, news release IR-2025-103, tax year 2026 inflation adjustments, October 9, 2025, read November 10, 2026, for the prior year's filing-year sentence, the 2026 standard deduction amounts and the 2026 rate thresholds.
• Internal Revenue Service, Revenue Procedure 2025-32, the underlying document for the tax year 2026 adjustments, cited by that release.