Social Security COLA 2027 calculator: what you keep after Medicare Part B and income tax
The cost-of-living adjustment (COLA) on Social Security benefits paid from January 2027 comes from the average consumer price index for wage earners (CPI-W) in July, August and September 2026, compared with the same three months of 2025. The Bureau of Labor Statistics publishes the September figure on Oct. 14, 2026 at 8:30 a.m. Eastern. Until then this calculator starts at 2.7%, the Social Security Trustees' June 2026 projection, and you can enter any rate. It then takes out what comes back out of the raise: the higher Medicare Part B premium, the rounding Social Security applies to every payment, and the extra federal and state income tax on a larger benefit.
Your benefits and income
Result
| For all of 2027 | Amount |
|---|
| Person | Monthly benefit, now → 2027 | Part B premium, 2026 → 2027 | Monthly deposit, now → 2027 |
|---|
| Income tax for a year | Without the raise | With the raise |
|---|
Which numbers are final, and when the rest will be
| Number | In the calculator | Final when |
|---|---|---|
| 2027 COLA | 2.7%, the Social Security Trustees' intermediate projection (June 2026) | Oct. 14, 2026, when the Bureau of Labor Statistics publishes the September CPI |
| Part B standard premium | $202.90 in 2026 (final); $209.50 in 2027, the Medicare Trustees' estimate | When CMS announces the 2027 premium. The 2026 premium notice was filed on Nov. 14, 2025. |
| Income-related amounts (IRMAA) | 2026 amounts (final); 2027 amounts are the Medicare Trustees' estimates | With the 2027 premium. The 2027 income brackets are not published yet. |
| Income tax | 2026 federal and state rules for both years | When the IRS and each state publish their 2027 figures |
The 2026 COLA was 2.8%. Social Security's notice for 2026 says the CPI for the third quarter of 2025 exceeded that of 2024 “by 2.8 percent (rounded to the nearest 0.1)”. For 2027 the Medicare Trustees write: “The estimated monthly premium for 2027 is $209.50.” CMS's notice for 2026 set the premium this way: “The standard monthly Part B premium rate for all enrollees for 2026 is $202.90”.
Sources: SSA, Cost-of-Living Increase and Other Determinations for 2026, 90 FR 49047 (Nov. 3, 2025); 2026 Annual Report of the Social Security Board of Trustees (House Document 119-163, June 18, 2026), Table V.C1; Bureau of Labor Statistics, Schedule of Releases for the Consumer Price Index; 2026 Annual Report of the Medicare Boards of Trustees (June 9, 2026); CMS, Medicare Part B monthly actuarial rates, premium rates and annual deductible for 2026, 90 FR 52063 (Nov. 19, 2025).
How the calculator works
- Your benefit after the COLA. Your current benefit times the COLA, rounded down to the next lower 10 cents, as the law rounds an increased benefit. Social Security applies the COLA to your primary insurance amount before other adjustments, so its figure can differ slightly from this.
- The Part B premium. $202.90 a month in 2026 and the $209.50 estimate for 2027, plus your income-related amount if you pay one.
- The hold-harmless rule. If the premium is taken out of your Social Security in December and January and you do not pay an income-related amount, the Medicare Trustees describe the rule as one that “limits the dollar increase in the premium to the dollar increase in an individual’s Social Security benefit”. At a 2.7% COLA and a $6.60 premium increase, that matters only for benefits below about $240 a month. It does not cover people new to Part B in 2027, people who pay Medicare directly, or people whose premium the state pays. Social Security's manual adds: “Anyone paying an Income-Related Monthly Adjustment Amount (IRMAA) does not get VSMI protection.”
- Rounding the deposit. The monthly payment, after the premium is taken out, is rounded down to the whole dollar.
- Income tax. A year of benefits before and after the COLA goes through the federal worksheet for taxing Social Security (up to 85% of benefits), the standard deduction, the extra deduction at 65 and the $6,000 senior deduction, and through your state's own rules for Social Security and retirement income. The difference is the tax on your raise. Both years use 2026 rules. The federal income levels at which benefits start to be taxed are fixed in law and do not rise with inflation, so a COLA can make more of a benefit taxable.
The tax engines are the ones behind our retirement tax calculator for all 50 states and Social Security tax calculator, where every state's rules and sources are listed.
Sources: 42 U.S.C. 415; 42 U.S.C. 1395r; 2026 Annual Report of the Medicare Boards of Trustees (June 9, 2026); SSA, POMS HI 01001.004, The Variable Supplementary Medical Insurance (VSMI) Premium; 26 U.S.C. 86 (taxation of Social Security benefits).
What the calculator leaves out
- Part D and Medicare Advantage premiums, and the Part D income-related amount (CMS has not published the 2027 amounts).
- Medigap premiums, Supplemental Security Income and state supplements.
- Tax withheld from your benefit, itemized deductions such as medical expenses, and local income taxes.
- The move of your income-related tier from 2024 income to 2025 income. Pick the tier you expect for 2027.
Parameters used, with sources
Loaded from the same file the calculation reads.
Test cases
Every case was computed by a separate reference implementation and by this page's code; the two agree to the cent. The cases cover all 50 states and DC, single and joint filers, the hold-harmless rule, income-related tiers, premiums paid directly or by Medicaid, and COLAs from 0% to 5%. The self-test reruns the comparison in your browser.
Rechecks and changes
- . First published, before the 2027 COLA is announced.
Dollars Ahead is not affiliated with the Social Security Administration, CMS or any state. This tool shows what published rules do to the numbers you enter. It is not financial or tax advice. Your Social Security notice and your tax return are the final word.