Social Security COLA: announcement date and formula

The Social Security cost-of-living adjustment is announced once a year, in October, and shows up in benefits paid the following January. The number itself is not a forecast or a policy decision: it falls out of a formula fixed in statute, applied to three months of price data. Two features of that formula are almost never spelled out — the index is the CPI-W rather than the headline CPI-U, and the comparison base is not mechanically the previous year. This page gives the current adjustment and the next determination date, then sets out the calculation, the calendar that produces it, and what happens in the years the formula returns nothing.

How the adjustment is calculated

Automatic adjustments were created in 1972 by P.L. 92-336, which added Section 215(i) to the Social Security Act, and took effect in 1975. The original text required inflation of at least three percent over the base period before an adjustment could be triggered; the Omnibus Budget Reconciliation Act of 1986 removed that threshold and replaced it with a requirement that the measured increase simply be greater than zero.

The statute compares two third-quarter averages of the Consumer Price Index for Urban Wage Earners and Clerical Workers. The Bureau of Labor Statistics publishes the CPI-W monthly; the Social Security Administration averages the July, August and September readings of the current year and measures the increase over the average for the cost-of-living computation quarter. The percentage is rounded to the nearest tenth of a percentage point, and the resulting benefit amount is rounded down to the next lower dime. The adjustment becomes effective in December and is payable in January, which is why an adjustment described everywhere as belonging to one year is technically effective in the preceding December.

The friction: three months, a narrower index, and a base that does not always move

The measurement window is three months long. Prices in the other nine months of the year enter the calculation only to the extent that they carry into July, August and September levels. A price shock in the fourth quarter has no effect on the adjustment announced two months earlier, and no effect on the following year’s either, except through its persistence into the next third quarter. This is a structural feature of the statute rather than an artefact, and it is the reason forecasts published before the September data are estimates and nothing more.

The index is the second point of divergence. The CPI-W is built on the spending patterns of households drawing at least half their income from hourly wages or clerical work, with at least one member employed for thirty-seven weeks of the previous twelve months — roughly thirty percent of the U.S. population. The headline CPI-U covers all urban consumers. The two indexes weight housing, medical care and transportation differently, so the CPI-W reading in any given month can differ from the number that leads the monthly inflation coverage. The Social Security Administration has no discretion here: the CPI-W is specified in regulation.

The third point is the comparison base. The statute does not compare the current third quarter to the previous third quarter; it compares it to the highest third-quarter average on record, known as the cost-of-living computation quarter. In most years these are the same thing. When the CPI-W falls or fails to exceed the prior benchmark, no adjustment is payable, benefits are held at their previous level, and the benchmark quarter is retained rather than reset. That happened after the third quarter of 2009 and again after 2010, so the adjustment payable in January 2012 was measured against the third quarter of 2008, three years earlier. The same mechanism applied after 2015: the adjustment payable in January 2017 was measured against the third quarter of 2014. Three payable years since 1975 have carried no adjustment at all.

The calendar that produces the number

The announcement date is not a scheduling decision so much as a consequence. The last input to the calculation is the September CPI, and the BLS publishes it at 8:30 a.m. Eastern Time on a date set in its annual release calendar, usually in the first half of October. The Social Security Administration has historically announced the adjustment the same day, but the announcement date itself is not published in advance and is not guaranteed to coincide.

The distinction matters when the release slips. The September 2025 CPI was published on 24 October 2025, later than the usual pattern, and the announcement of the adjustment payable from January 2026 came the same day. A lapse in appropriations had disrupted the BLS release calendar that autumn, shifting or cancelling a long list of releases; the September CPI was not among those BLS listed as formally rescheduled, so the two facts are stated here side by side rather than as cause and effect. Anyone building a calendar around the announcement rather than around the BLS release is anchoring on the wrong event.

What moves alongside it

The adjustment does not stop at Social Security benefits. Supplemental Security Income payments and railroad retirement tier 1 benefits are raised by the same percentage, and railroad retirement tier 2 benefits by roughly a third of it. Veterans’ pension benefits, survivors pension benefits and Dependency and Indemnity Compensation for parents are adjusted automatically by the same percentage under Title 38; disability compensation and Dependency and Indemnity Compensation for spouses and children usually follow, but require annual legislation. Civil Service Retirement System and military retirement adjustments are not triggered by the Social Security figure, yet use the same measuring period and formula. Federal Employees Retirement System adjustments match it only when inflation is at or below two percent, and fall short of it otherwise.

Several program parameters indexed to wages rather than prices — the taxable maximum, the retirement earnings test exempt amounts, the substantial gainful activity amount for the blind — can only be increased in a year when an adjustment is payable. In 2010, 2011 and 2016 they were frozen alongside benefits, then jumped when the sequence resumed, catching up on the wage growth of the intervening years.

The index that drives all of this is the same CPI series that shapes rate expectations, discussed across the macro-financial regimes pillar. The underlying series and releases Eco3min tracks are collected in research and data, and the current reading of U.S. and European indicators is kept in macro watch. For another calendar question where the published rule and the observed practice diverge, see is the U.S. stock market open today.

Frequently asked questions

Last updated — 12 August 2026