What the COLA input changes
The COLA calculator applies a percentage increase to a monthly benefit that you type. Its default is 3.6%, the announced 2027 adjustment, but the field remains editable for scenario comparisons. It also accepts an optional Medicare premium before and after the adjustment. Those are entirely user-entered amounts; the page does not supply or imply any 2027 Part B premium figure. A withholding percentage can estimate a federal amount withheld from the new gross benefit.
Formula used in this page
The new gross amount is current monthly benefit multiplied by one plus the entered COLA divided by 100. Monthly change is new minus old, and annual change is the monthly difference times 12. For a net-deposit comparison, the tool subtracts the old premium from the old benefit and the entered new premium from the new gross benefit. The withholding line applies the selected percentage to the new gross monthly benefit. Each of these is a simple scenario; actual SSA rounding and deductions appear on an official notice.
The five-year table starts with the post-2027 amount, then compounds it once per row using the future COLA assumption. The later percentages are not predictions and can be set to zero. Medicare premiums, tax withholding, eligibility changes, and other deductions are not projected across those rows.
Worked hypothetical example
For an illustrative $2,000 monthly benefit and a 3.6% increase, the gross adjustment is $2,000 × 0.036, or $72 each month. The new gross amount is $2,072, and the annual gross change is $864. If a reader enters hypothetical premiums of $150 before and $165 after, the deposits before tax withholding would be $1,850 and $1,907. The net change under those entered values is $57 monthly. Those premium numbers are sample inputs only, not published Medicare rates.
Why a deposit can differ from the gross adjustment
A Social Security cost-of-living adjustment applies to the benefit amount, while the deposit reflects deductions and withholding. A changed Medicare premium can affect the amount deposited. Federal tax withholding also changes cash received, and taxation of benefits is a separate calculation explained in the federal tax estimator. SSA's COLA notice has the actual rounded amount and individual deductions.
The 2027 adjustment begins with benefits payable in January 2027. SSA bases COLAs on changes in the CPI-W between the third quarter of the last COLA year and the third quarter of the current year. If there is no increase under the rule, no COLA applies. The official announcement and historical series are linked below.
How to use the result
First enter the gross monthly amount from a current statement or notice. Keep premium fields at zero if you only want the gross change, or enter your own known old and expected new deductions. Treat the later five-year values as a mathematical illustration. The tool does not model benefit eligibility, a spouse's record, taxes on a full return, or possible future legal changes.
BenefitWise is an independent site and is not affiliated with or endorsed by SSA. Your official amount is on your my Social Security statement; the calculator is an estimate, not advice.