Obamacare tax rates come down to three numbers on your federal return: a 3.8% surtax on investment income above certain thresholds, a 0.9% surtax on wages and self-employment income above those same thresholds, and the Premium Tax Credit, a sliding-scale subsidy that either boosts your refund or forces you to repay part of what the Marketplace advanced to your insurer. For 2026, the enhanced subsidies that held Marketplace premium costs down from 2021 through 2025 have expired, so the older, stricter income limits are back in force.
The 3.8% Net Investment Income Tax
The ACA added a 3.8% surtax on net investment income for higher earners. The tax applies to the lesser of your net investment income or the amount by which your Modified Adjusted Gross Income exceeds the threshold for your filing status.1Internal Revenue Service. Topic No. 559, Net Investment Income Tax
The thresholds are $250,000 for married filing jointly, $125,000 for married filing separately, and $200,000 for single or head of household filers.
Income that counts as investment income includes interest, dividends, capital gains, rental and royalty income, and non-qualified annuities. It does not include wages, Social Security benefits, unemployment compensation, or most self-employment income.2Internal Revenue Service. Net Investment Income Tax Gain on the sale of your primary home that qualifies for the regular income exclusion is also excluded.
Here’s how the math works. A single filer with $180,000 in wages and $50,000 in investment income has a MAGI of $230,000. That’s $30,000 over the $200,000 threshold. The 3.8% applies to the lesser of the $50,000 investment income or the $30,000 excess, so the tax is 3.8% of $30,000, which comes to $1,140. You calculate and report the tax on Form 8960 and attach it to your return.3Internal Revenue Service. Instructions for Form 8960
These thresholds are fixed in statute and are not adjusted for inflation, so more taxpayers cross them each year as incomes rise.
The 0.9% Additional Medicare Tax
The 0.9% surtax lands on wages and self-employment income above the same dollar thresholds: $250,000 for joint filers, $125,000 for married filing separately, and $200,000 for single or head of household filers.4Internal Revenue Service. Questions and Answers for the Additional Medicare Tax It sits on top of the standard 1.45% Medicare tax that applies to all wages.
A married couple filing jointly with combined wages of $300,000 pays the extra 0.9% only on the $50,000 exceeding their $250,000 threshold, which works out to $450. You report it on Form 8959.
One wrinkle catches dual-income couples. Employers withhold the Additional Medicare Tax once an individual employee’s wages pass $200,000 in a calendar year, regardless of filing status.4Internal Revenue Service. Questions and Answers for the Additional Medicare Tax If you and your spouse each earn $150,000, neither employer withholds anything extra, because neither of you individually crosses $200,000. But your combined $300,000 is $50,000 past the joint threshold, and you’ll owe the 0.9% on that excess at filing. Self-employed taxpayers face the same rule and need to account for it when calculating estimated payments.
These thresholds are also not indexed for inflation and have remained unchanged since 2013.
Premium Tax Credit Eligibility for 2026
The Premium Tax Credit offsets the cost of health insurance bought through the ACA Marketplace. Eligibility hinges on household income falling between 100% and 400% of the Federal Poverty Level for your family size.5Internal Revenue Service. Eligibility for the Premium Tax Credit The credit works on a sliding scale: the lower your income within that band, the larger your credit. Local plan pricing and where you live also affect the amount.
From 2021 through 2025, Congress temporarily removed the 400% FPL ceiling and capped everyone’s premium contribution at 8.5% of household income. Those enhancements expired on December 31, 2025.6Internal Revenue Service. Updates to Questions and Answers About the Premium Tax Credit Starting with the 2026 plan year, the original limits are back. If your household income exceeds 400% of the FPL, you get no credit at all, and you must repay every dollar of advance payments made on your behalf during the year.
For 2026, the Federal Poverty Level for a single person in the contiguous 48 states is $15,960, putting the 400% cutoff at $63,840. For a family of four, the poverty level is $33,000, with the 400% ceiling at $132,000.7HHS ASPE. 2026 Poverty Guidelines – 48 Contiguous States A few hundred dollars over that line loses the entire credit. That’s the “subsidy cliff.”
The credit compares your MAGI to the cost of the second-lowest-cost Silver plan in your area. For this purpose, MAGI is your adjusted gross income plus any tax-exempt interest, nontaxable Social Security benefits, and foreign earned income.8Internal Revenue Service. Modified Adjusted Gross Income
Most enrollees take the credit as advance monthly payments sent directly to their insurer. After year-end, the Marketplace issues Form 1095-A showing what was paid. Keep it; you can’t complete your return without it.
Reconciling Advance Payments on Your Return
If you received advance Premium Tax Credit payments, you have to file Form 8962 with your federal return. The form reconciles what was advanced against the credit you actually qualify for based on final income.9Internal Revenue Service. Premium Tax Credit – Claiming the Credit and Reconciling Advance Credit Payments You use Form 1095-A to complete it.
When your actual income comes in lower than the estimate you gave the Marketplace, your final credit is larger than what was advanced, and the difference is added to your refund. When your income comes in higher, you owe money back.10Internal Revenue Service. Reconciling Your Advance Payments of the Premium Tax Credit
For households below 400% of the FPL, the repayment is capped. The current caps from the Form 8962 instructions are:11Internal Revenue Service. Instructions for Form 8962
- Below 200% FPL: $375 single, $750 for other filing statuses
- 200% to under 300% FPL: $975 single, $1,950 for other filing statuses
- 300% to under 400% FPL: $1,625 single, $3,250 for other filing statuses
At 400% of the FPL or higher, there is no cap. You repay the entire excess.11Internal Revenue Service. Instructions for Form 8962 With the enhanced caps gone for 2026, someone who nudged just over the 400% line can owe thousands of dollars back.
You can also claim the credit at filing time even if you took no advance payments. If you paid full price for a Marketplace plan and your income qualifies, Form 8962 can produce a refundable credit.
Skipping Form 8962 doesn’t work. E-filed returns without it get rejected outright when advance payments were received.12Internal Revenue Service. How to Correct an Electronically Filed Return Rejected for a Missing Form 8962 Paper returns get accepted, then the IRS writes to you for the missing form. Failing to reconcile can also cut off your eligibility for advance payments in future years.9Internal Revenue Service. Premium Tax Credit – Claiming the Credit and Reconciling Advance Credit Payments Filing a late return with Form 8962 attached can restore eligibility.
What About the Individual Mandate
The federal penalty for going without minimum essential coverage was reduced to zero starting with tax year 2019.13Internal Revenue Service. Questions and Answers on the Individual Shared Responsibility Provision You owe the IRS nothing federally for being uninsured.
Several states and the District of Columbia have enacted their own individual mandates with their own penalties.14HealthCare.gov. Exemptions From the Fee for Not Having Coverage These are assessed through the state return, not your federal filing. If you live in one of those states, check your state tax agency for current penalty amounts and exemptions.
Your W-2 Box 12 Code DD
If you have employer-sponsored coverage, your W-2 may show a dollar amount in Box 12 with Code DD. That’s the total cost of your employer-provided health coverage, both the employer’s share and yours.15Internal Revenue Service. Form W-2 Reporting of Employer-Sponsored Health Coverage The ACA requires the reporting, but the figure is informational only. It isn’t taxable income, and it doesn’t change anything on your return.