Free calculator · tax year 2026
MAGI calculator for IRMAA, the ACA credit and the NIIT
One AGI, three modified AGIs. Enter a year’s income to see each one, what it adds back, and how close it sits to its line.
Adjusted gross income, 2026: $92,140.
Adjusted gross income, 2026$92,140Plan withdrawals and Roth conversions together
See how cash, IRA, Roth and brokerage withdrawals cover spending, with federal and state tax.
Three programs start from the same AGI of $92,140 and add back different things: $96,140 for IRMAA, $101,900 for the ACA credit, $92,140 for the investment income tax.
| MAGI for | Formula | Amount | Against its line |
|---|---|---|---|
| Medicare IRMAA | AGI + tax-exempt interest | $96,140 | $121,860 under the first surcharge (sets 2028 premiums; estimate on 2026 tiers) |
| ACA premium tax credit | AGI + tax-exempt interest + Social Security not taxed | $101,900 | $17,300 over 400% of the poverty line |
| Net investment income tax | AGI + excluded foreign earned income (none here) | $92,140 | $157,860 under the 3.8% tax threshold |
Taxable Social Security in AGI: $32,640; the other $5,760 counts only for the ACA.
Calculations, not tax, legal or investment advice.
Method and sources
AGI is your income on Form 1040 line 11, with Social Security counted only up to its taxable part under the IRS worksheet. Each program then modifies it. Medicare’s IRMAA adds tax-exempt interest. The ACA premium tax credit adds tax-exempt interest and the part of Social Security that was not taxed. The net investment income tax adds only foreign earned income excluded from AGI, which this page does not ask about, so for most retirees it equals AGI.
IRMAA reads the MAGI from two years earlier, so 2026 income sets 2028 Medicare premiums; this page uses the latest published tiers as an estimate. The ACA line is 400% of the federal poverty line for the household size and region you enter; Alaska and Hawaii have their own, higher poverty lines. The 2026 federal tables are used; itemized deductions do not change AGI and are not asked.
Tables and sources
- IRS Publication 915, Social Security and Equivalent Railroad Retirement BenefitsIRC §86 base amounts; Pub 915 Worksheet 1; not indexed · 2026 · www.irs.gov
- CMS fact sheet: 2026 Medicare Parts A & B Premiums and Deductibles (2025-11-14)Part B and Part D income-related monthly adjustment amounts; set from MAGI two tax years earlier · 2026 · www.cms.gov
- HHS 2025 Poverty Guidelines (Federal Register 2025-01377); IRS Premium Tax Credit Q&A A72026 coverage uses the 2025 HHS poverty guidelines (48 states + DC); the enhanced credit lapsed after 2025, so eligibility stops above 400% FPL · www.federalregister.gov
- IRS: Questions and Answers on the Net Investment Income TaxIRC §1411; thresholds are statutory and not indexed · 2026 · www.irs.gov