ACA Subsidies Explained
Most people who buy on the Marketplace do not pay the full sticker price of their plan. They pay a lower monthly premium because the federal government helps, and many also pay less when they actually use care. Those two kinds of help have different names, different rules, and different traps, and confusing them is one of the commonest reasons people pick the wrong plan.
The two subsidies, in one paragraph
The premium tax credit lowers your monthly premium. It is based on your household income, your household size, and the price of the second-lowest-cost Silver plan in your area, called the benchmark plan. Cost-sharing reductions lower what you pay when you use care, your deductible, copays, coinsurance, and out-of-pocket maximum. They are only available on Silver plans, and only to households with incomes between 100% and 250% of the federal poverty level. You can get one without the other, but only Silver gives you both.
How the premium tax credit is worked out
The formula, in plain terms, is: benchmark premium minus your required contribution. Your required contribution is a percentage of your household income, set by a sliding scale in the law, and it rises as income rises. The difference, if positive, is your premium tax credit. You can take it in advance, month by month, so your premium is lower from the start, or you can claim it when you file your taxes. Most people take it in advance, because that is the point of the help.
An example, clearly labeled as illustrative, shows why the benchmark matters. Suppose the benchmark Silver plan in your area costs 600 dollars a month, and your required contribution works out at 300 dollars a month. Your credit is 300 dollars a month, and you can apply it to any metal tier plan. If you pick a Bronze plan costing 450 dollars, your premium after the credit is 150 dollars. If you pick a Gold plan costing 700 dollars, your premium after the credit is 400 dollars. The credit does not change when you change tiers. Only the plan price does.
Who qualifies for a premium tax credit?
Under the rules restored when the enhanced credits expired at the end of 2025, premium tax credits are available to households with incomes between 100% and 400% of the federal poverty level, who are not offered affordable job-based coverage, who are not eligible for Medicare, Medicaid, or children's coverage, and who file taxes as required. For 2026 coverage, that range is roughly 15,650 to 62,600 dollars for a single person and 32,150 to 128,600 dollars for a family of four, based on the poverty guidelines used for that coverage year. For 2027 coverage, the top of the range is reported at about 63,840 dollars for one person and about 132,000 dollars for a family of four. Poverty guidelines are updated annually, so the exact dollar figures for your year are the ones your marketplace uses, not a figure you remember from a previous year.
Below 100% of the poverty level, the picture depends on your state. In states that expanded Medicaid, very low-income adults are usually covered by Medicaid instead. In states that have not expanded, some people fall into a coverage gap: too poor for a premium tax credit, but not eligible for Medicaid under that state's rules. That gap is a state policy outcome, not something the Marketplace application can fix, and it is worth knowing about before you assume a credit is available at any income.
Cost-sharing reductions: the Silver-only benefit
Cost-sharing reductions, often shortened to CSRs, do not lower your premium. They make a Silver plan act like a richer plan. A standard Silver plan pays about 70% of average covered costs. With cost-sharing reductions, that figure rises to 94% for incomes up to 150% of the poverty level, 87% for incomes above 150% up to 200%, and 73% for incomes above 200% up to 250%. In practice that means a much lower deductible, lower copays, and a lower out-of-pocket maximum, automatically, when you enroll in a Silver plan. Choose Bronze or Gold at the same income and you lose the benefit entirely, even though your premium tax credit stays the same.
Advance payments and reconciliation
When you take the credit in advance, you are estimating your income for the year ahead. At tax time, the Internal Revenue Service compares your estimate with your actual income on Form 8962 and reconciles the difference. If you earned more than you estimated, you may have to pay some of the advance credit back. If you earned less, you may get an additional credit. That reconciliation is the subject of its own guide on this site, because it is where a good estimate matters most, and where crossing the 400% poverty level cliff can have a large effect under the restored rules.
Sources: HealthCare.gov, premium tax credit and cost-sharing reduction pages; 26 U.S.C. section 36B (premium tax credit); 42 U.S.C. section 18071 (cost-sharing reductions); Congressional Research Service, health insurance premium tax credits and cost-sharing reductions.