The Senior Citizens League’s newest projection for Social Security’s 2027 cost-of-living adjustment is 3.5%. It is an estimate, not a government figure. Social Security has not set next year’s COLA and has said it will announce the official number in October 2026, after the last piece of inflation data the formula needs is published. If 3.5% holds, TSCL’s own math says it would add $67.90 to the average monthly benefit.
A 3.5% Estimate, Trimmed Down From 3.6%
TSCL now projects a 2027 COLA of 3.5%, according to the group’s Sept. 11, 2026 update, released with roughly a month left before Social Security’s own announcement. That figure is lower than the group’s prior projection: an Aug. 12, 2026 estimate from the same organization put the number at 3.6%, which TSCL described at the time as 0.8 percentage points above the actual 2026 COLA of 2.8%. The estimate has moved as more of the year’s inflation data has come in, which is the nature of a projection built before the underlying numbers are final. It is expected to keep shifting slightly until Social Security calculates the real figure.
Before the notice arrives: Social Security’s own COLA notice won’t confirm a 2027 number until October, and a 3.5% estimate is not a substitute for checking the increase against the line items on that actual notice once it lands. Open The Social Security Check Protection Kit.
What 3.5% Would Add To The Average Check
TSCL calculates the impact using its own baseline: the group puts the current average Social Security benefit at $1,940.08 a month, and says a 3.5% COLA would raise that to $2,007.98, an increase of $67.90, per the same Sept. 11, 2026 release. That average-benefit figure is TSCL’s own reference point rather than a Social Security-published number, so an individual beneficiary’s dollar increase will track their own current check rather than the $1,940.08 baseline. The percentage is what carries over, not the flat $67.90 figure, for anyone whose benefit differs from the group’s average.
Why This Isn’t The Official Number Yet
Social Security calculates the real COLA using the Consumer Price Index, and the agency has confirmed its own timeline: “We determined a 2.8-percent COLA on October 24, 2025. We will announce the next COLA in October 2026,” according to Social Security’s official COLA summary page. The last data point that calculation depends on is the September 2026 Consumer Price Index, which the Bureau of Labor Statistics is scheduled to publish on Wednesday, Oct. 14, 2026, at 8:30 a.m. Eastern, the same date TSCL’s Sept. 11 release names as the expected announcement. Until that report is out and Social Security runs its own formula, 3.5% remains TSCL’s estimate rather than a set benefit increase.
The formula itself is fixed, even though the September number is not. Social Security’s methodology page shows the agency averages the CPI-W index across the third quarter, July, August and September, of the current year, then compares that average against the same three-month average from the last year a COLA took effect, with the percentage difference rounded to the nearest tenth of a point, per the Social Security Administration’s COLA calculation page. July and August 2026 data are already locked in; only the September figure due Oct. 14 remains open, which is why TSCL’s projection has narrowed with each update rather than swinging wildly the way an early-year guess might.
A Larger Raise Than This Year’s
However the final number lands, it is on track to beat what beneficiaries got this year. Social Security’s own COLA summary confirms the 2026 adjustment was 2.8%, a full percentage point below TSCL’s current 3.5% projection for 2027. For a household budgeting around a fixed monthly check, the difference between a 2.8% raise and a 3.5% one compounds every month it’s in effect, which is part of why TSCL revisits its projection with each new round of inflation data rather than publishing a single estimate and leaving it unchanged for months.
Reading A COLA Notice Once The Real Number Arrives
TSCL’s 3.5% projection gives beneficiaries a preview, but the figure that actually changes a monthly deposit is the one Social Security prints on its own COLA notice in October, net of any Medicare premium adjustment folded into the same letter. That notice arrives ahead of the January payment it describes, and translating its lines into an actual dollar change is a separate task from simply knowing the percentage.
The Social Security Check Protection Kit walks through how to read a COLA and benefit notice line by line alongside the 2026 payment calendar showing when an adjusted deposit is due to arrive.
Read how to check a COLA notice in The Social Security Check Protection Kit.
This article was produced with AI assistance and checked against the primary sources linked above.
David M. Keller is a finance writer based in Columbus, Ohio, covering personal finance and consumer-focused economic topics. He earned his degree in journalism from Ohio University and began his career reporting on local business and economic trends for a regional media outlet. Since then, he has contributed to a variety of online publications, focusing on clear, practical coverage of topics such as cost of living, debt, and everyday financial decision-making.
