September Inflation at 3.9%: What It Means for Social Security's 2027 Raise

Every fall, tens of millions of Americans who get Social Security wait for one number: next year's cost-of-living adjustment, or COLA. That number has now been decided for 2027.

The Motley Fool reports that September inflation came in at 3.9%, a reading that helped set the 2027 COLA. PBS reports that the adjustment "is set" and has gathered expert advice on what beneficiaries should know. Other coverage looks at two related questions: how much of the raise rising Medicare costs could take back, and how much of a worker's pay will face Social Security tax in 2027.

What happened

According to The Motley Fool, inflation for September 2026 was 3.9%. Inflation measures how fast prices are rising. A 3.9% reading means that, on average, the prices in the measured basket of goods and services were 3.9% higher than they were a year earlier.

PBS reports that the 2027 COLA has been finalized. The headlines we reviewed don't give the exact COLA percentage, so we won't guess it here. Beneficiaries can find the official figure on the Social Security Administration's website or in its notices to them.

NewsNation looks at how a higher Medicare premium could "trim" retirees' Social Security raise. Yahoo Finance covers the separate question of how much of a worker's earnings will be subject to Social Security tax in 2027.

How the COLA works (background)

The COLA exists so Social Security checks keep up with rising prices. Under federal law, the adjustment is tied to a government inflation index called the Consumer Price Index for Urban Wage Earners and Clerical Workers (CPI-W).

In general, officials compare the average CPI-W for July, August and September with the same three months a year earlier. The percentage increase becomes the next year's COLA, and it shows up in payments starting in January. That's why September's inflation report matters so much: it supplies the last piece of data.

The 3.9% figure in the headline may not be the exact number used in the formula. News reports often cite the broader Consumer Price Index, and the COLA is based on a three-month average of the CPI-W. The two can differ slightly.

Why Medicare and payroll taxes come up

Many retirees have their Medicare Part B premium taken straight out of their Social Security check. When that premium goes up, part of the COLA gets used up before the money reaches the retiree. NewsNation's coverage focuses on this point: the raise you see on paper and the increase in your actual deposit can be different.

On the worker side, Social Security is paid for through a payroll tax. That tax only applies to earnings up to a yearly limit, often called the wage base or taxable maximum. The limit is usually adjusted each year based on wage growth across the country. Yahoo Finance's coverage looks at where that limit falls for 2027. It mainly affects higher earners, because pay above the limit isn't subject to the Social Security portion of the tax.

Why it matters for everyday people

If you get Social Security, the COLA sets how much your monthly benefit changes in 2027. It's worth watching your official notice from the Social Security Administration, which should show your new benefit and any Medicare deductions.

Keep in mind that a COLA is meant to help you keep pace with prices, not to get ahead of them. Your own costs may rise faster or slower than the national average, depending on what you spend your money on, such as housing, food or medical care.

If you're still working, the 2027 wage base tells you how much of your pay will face Social Security tax next year. Together, these numbers affect household budgets on both sides of retirement.