Retirees waiting to see how much bigger their Social Security check might get in January are getting only the second of three pieces of data this morning. The Bureau of Labor Statistics is scheduled to publish the August Consumer Price Index at 8:30 a.m. Eastern on Friday, September 11 — one of three monthly inflation readings the Social Security Administration needs before it can calculate 2027’s cost-of-living adjustment. Nobody, including the agency itself, has the actual number yet, and won’t for another month.
How Three Months of Data Turn Into One Raise
Social Security’s annual increase isn’t decided by Congress, a committee vote, or a press release timed to any particular news cycle. It comes out of a fixed statutory formula tied to one specific measure of inflation. Under the law, the Social Security Administration compares the average Consumer Price Index for Urban Wage Earners and Clerical Workers, known as CPI-W, across the third quarter of the current year against the third quarter of the last year a COLA was determined. Whatever that percentage change works out to becomes next January’s raise.
The third quarter is July, August and September. That structure means the calculation cannot run until three separate monthly CPI-W readings exist. July’s reading already published last month. August’s publishes this morning. September’s — the one that actually closes out the quarter — is still more than a month away. Only once all three are in hand does the SSA have anything to average, compare and announce.
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This Morning’s Reading Is the Middle Piece, Not the Answer
August’s CPI-W figure lands on the Bureau of Labor Statistics’ regular monthly release schedule, at 8:30 a.m. Eastern on September 11. The same BLS release calendar already lists the third and final reading in the sequence — September’s data — for October 14, also at 8:30 a.m. Eastern. That’s the release that actually finishes the quarter and gives the SSA something to calculate.
Expect plenty of headlines the moment this morning’s figure posts, and it is a reasonable data point for any household tracking inflation. It is not, on its own, a Social Security number. The statutory formula runs on a three-month average measured against the same quarter a year earlier, not any single month in isolation, so today’s release only narrows the range — it doesn’t set the raise.
July’s Reading Already Banked the First Third
The first of the three inputs is no longer a projection. The Bureau of Labor Statistics reported that the CPI-W rose 3.4 percent over the 12 months ending in July 2026, putting the index at a level of 327.104. That’s a real, published number — the only piece of the eventual third-quarter average that has moved from forecast to fact so far.
One month of data doesn’t reveal where the full quarterly average will land, since the formula compares three-month averages rather than a single snapshot. But it rules out some of the more extreme guesses currently circulating, and it’s the baseline this morning’s August figure will be measured against.
The Number That Actually Sets the Raise Doesn’t Land Until October
Even after today, the SSA still can’t announce anything. The September CPI-W reading is scheduled for October 14 — the release that lets the agency average all three third-quarter months, compare the result to the same quarter a year earlier, and calculate an actual percentage. Last year, the SSA followed that same pattern: after the third reading closed out the 2025 third quarter, the agency announced a 2.8 percent COLA for 2026, effective with January 2026 benefits.
Recent raises give a sense of the range that formula has produced: 2.8% for January 2026, 2.5% for January 2025, 3.2% for January 2024, and an outsized 8.7% for January 2023. Where 2027 lands inside or outside that range depends entirely on data that doesn’t exist yet — including the reading due this morning.
The Fine Print Behind the Check Amount
Even once a percentage is set, it does not turn into a check increase in a straight line. Social Security’s own explanation of how a COLA is applied to a retirement benefit walks through several rounding steps: the percentage is applied first to a worker’s primary insurance amount, with the result truncated down to the next lower dime, then adjusted for filing before or after normal retirement age, and only after any Medicare premium is subtracted does the agency truncate the final monthly payment down to the next lower dollar. Two retirees with the same COLA and a similar starting benefit can see slightly different-looking increases once that rounding runs its course.
A separate rule, the hold-harmless provision, keeps a rising Medicare Part B premium from eating into that same check. As Social Security describes the rule, a beneficiary who already has Part B premiums deducted from a November and December benefit is protected from a net year-over-year decrease, though the protection does not extend to someone enrolling in Part B for the first time, a beneficiary who pays an income-related premium, or a person whose premium is already covered by a state Medicaid agency.
No Official 2027 Figure Exists — From Anyone
Any specific percentage attached to “the 2027 COLA” that’s already circulating is not a government number. The Social Security Administration has not calculated, confirmed or previewed a figure, and by its own description of the process, it cannot until the third-quarter data is complete. Outside organizations sometimes publish early, unofficial estimates based on partial-year data — but those are projections, not the calculation, and estimates like them have missed in both directions in past years.
Why Some Years Got No Raise At All
The statutory formula cuts both ways: it can also produce nothing. If the third-quarter CPI-W average does not come in higher than the average from the last year a COLA was paid, the law does not allow a cut — it simply pays no increase. According to the full COLA history Social Security’s Office of the Chief Actuary publishes, that has happened three times since automatic annual adjustments began in 1975: 2009, 2010, and 2015. In each of those years, the same third-quarter comparison now underway for 2027 simply did not clear the bar, and beneficiaries’ checks carried over unchanged into the following January.
This article was produced with AI assistance and reviewed by a human editor. Figures are linked to their primary sources; where a claim could not be verified from the public record, we say so.
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