One more month of data will determine how much of an increase Social Security recipients will receive in 2024.

By law, the annual increase – known as the Cost of Living Adjustment, or COLA – is based on average inflation during July, August and September as measured by the Consumer Price Index for Urban Wage Warners and Clerical Workers, or CPI-W., according to the nonpartisan The Senior Citizens League. Inflation from those three months is added together and averaged and then compared with the third quarter from the same time the previous year. The percent of the difference between the two amounts is the COLA.

The CPI-W rose 3.6% in July and 3.4% in August.

Generally speaking, the Labor Department releases inflation data around the middle of the month, so the next COLA will likely not be known until around Oct. 15.

The latest estimate put it at 3.2%, far below last year’s 8.7% boost. This year’s average monthly retirement benefit is $1,790, a figure that would grow by $57.30 with a 3.2% increase.

Medicare premiums will eat into an increase

While an increase of at least 3% is likely, beneficiaries won’t know exactly how much more they will receive until Medicare premiums are announced, which is typically in November, according to TSCL. Medicare Part B premiums are automatically deducted from Social Security benefits before they are received.

In an annual report released in March, the Medicare Trustees forecast monthly Part B premiums to increase from $164.90 to $174.80. That estimate, however, didn’t include Medicare’s coverage for lecanemab, known by the name Leqembi, a new Alzheimers drug, which is expected to cost as much as $26,000 per year without insurance.

Based on those spending estimates, TSCL forecasts that costs associated with the drug will add about $5 per month to the Part B premium, potentially raising the 2024 premium to about $179.80 per month.