The Social Security cost-of-living adjustment
Benefits rise each year by a formula written into law, not by a vote. This is the adjustment in force, what can be said about the next one, and how the number is made.
How the number is made
The adjustment is set by a formula in the Social Security Act, and it runs on one specific price index: the Consumer Price Index for Urban Wage Earners and Clerical Workers, CPI-W, published monthly by the Bureau of Labor Statistics. It is not the headline CPI that most inflation coverage quotes, which is the index for all urban consumers, though the two usually move together.
The calculation takes the average of the CPI-W for July, August and September and compares it with the average for the same three months of the last year in which an adjustment took effect. The percentage increase, rounded to the nearest tenth of a percent, is the COLA. If prices fell, the adjustment is zero — it is never negative, and benefits are never cut by it. That has happened three times, in 2010, 2011 and 2016.
Because the September index is published in October, that is when SSA announces the figure. It takes effect with December benefits, which are paid in January — so the first cheque that reflects a new COLA arrives in the new year.
Why it needs no vote
Social Security is mandatory spending: the benefit rules are written into permanent law and the outlay is whatever those rules produce. The COLA is part of those rules. Congress does not pass it, appropriate it or approve it each year, and it would take a change in the law itself to alter the formula. That is what makes it a clean example of how the larger part of the federal budget moves without anyone taking a vote.
What the headline number does not tell you
The COLA is applied to the gross benefit. For most retirees the Medicare Part B premium is deducted from the same payment, and that premium is set separately and can rise by a different amount. When it rises faster than the COLA, the increase a person actually sees is smaller than the percentage announced — and a hold-harmless provision prevents the net payment from falling for most, but not all, beneficiaries. The announced figure is the right number to quote; it is not the change in anyone's deposit.
What the adjustment adds
The in-force adjustment applied to a benefit you type. Your own notice from the Social Security Administration is the authority.
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Applies the 2.8% adjustment effective 2025-12. Rounded down to the dollar, as the Social Security Administration does. Medicare premiums and withholding are not included, so a real payment differs.
An illustration, not advice.
Recent adjustments
| Effective | COLA |
|---|---|
| December 2025 | 2.8% |
| December 2024 | 2.5% |
| December 2023 | 3.2% |
| December 2022 | 8.7% |
| December 2021 | 5.9% |
| December 2020 | 1.3% |
| December 2019 | 1.6% |
| December 2018 | 2.8% |
| December 2017 | 2.0% |
| December 2016 | 0.3% |
Source: SSA's annual determination notices in the Federal Register. Each year's figure is the one stated in that year's notice; the table shows the consecutive years the notices cover. Retrieved Oct 17, 2026, 1:02 a.m. ET.