The main subsidy is the premium tax credit: based on your expected household income for the coverage year, calculated as MAGI, it cuts your monthly marketplace premium, applied in advance.
A second type, cost-sharing reductions, lowers deductibles and copays for Silver plans in qualifying income ranges. Two rules matter: the credit is reconciled at tax time, so overestimates of need get paid back, making prompt income updates essential; and affordable employer coverage or Medicaid eligibility disqualifies you. HealthCare.gov's estimator shows your number from household size, state, and income.
What to do
Common questions
What is a health insurance subsidy?
A health insurance subsidy is government money that lowers what you pay for marketplace coverage, and the main one is the premium tax credit. The mechanics: when you apply on HealthCare.gov you estimate your household income for the coverage year, and the marketplace calculates a credit applied immediately to cut your monthly premium. HealthCare.gov notes that marketplace savings are based on your expected household income for the year you want coverage, not last year's income, and the marketplace uses a number called modified adjusted gross income, MAGI, to determine whether you qualify. The second subsidy type is cost-sharing reductions, extra savings that lower your deductible and copays, available only if you pick a Silver plan and your income falls in the qualifying range. The rules that matter: the credit is reconciled on your tax return, so if your income ends up higher than you estimated, you may have to pay some back, which is why HealthCare.gov advises making your best estimate and updating your application when income changes; and you generally cannot get the credit if you have an offer of affordable employer coverage or qualify for Medicaid. The fastest way to see your own number: the savings estimator on HealthCare.gov with your household size, state, and income.