More than 71 million Americans will learn the size of next year's Social Security raise in five days.

The Social Security Administration plans to announce the 2027 cost-of-living adjustment, or COLA, on Wednesday, Oct. 14. That follows the Bureau of Labor Statistics release of September inflation data at 8:30 a.m. ET that day, AS USA reported. The raise takes effect in January and also applies to Supplemental Security Income.

Until then, every number is an estimate. The COLA is based on a price index called CPI-W. The government compares its average for July, August and September with the same months a year earlier. Two of the three readings are already in: July at 327.104 and August at 328.481, 24/7 Wall St. reported.

Forecasts vary. The Senior Citizens League puts the raise at 3.5%. AARP estimated 3.6%, and the Committee for a Responsible Federal Budget had the lowest estimate at 3.2%, 24/7 Wall St. said. Any of those would beat this year's 2.8% raise.

In dollars, a 3.5% raise would add about $73 a month to the average retired worker's check, which was about $2,088 in August, according to the outlet.

Medicare may shrink that gain. For most retirees, the Part B premium comes straight out of the Social Security check. It rose $18 to $203 this year, eating nearly a third of the 2026 raise. The 2026 Medicare Trustees Report projects a smaller increase for 2027, to about $210, 24/7 Wall St. reported. With a 3.5% raise, that would leave the average retiree about $66 more a month. The official premium usually comes in November.

The Senior Citizens League also argues the CPI-W does not fully reflect costs that matter most to older people, such as health care and housing, AS USA reported.

What we know: The official 2027 raise will be announced Oct. 14.
What we don't: The final percentage, which depends on September's inflation data.