Quick Answer: Household size is the count of people whose incomes are pooled when comparing to the [Federal Poverty Level](/federal-poverty-level). For ACA credits, your household is your tax return: you, your spouse (if filing jointly), and claimed dependents. Medicaid assigns each person their own count; a parent and child in the same home can have different household sizes. Per [HealthCare.gov](https://www.healthcare.gov/income-and-household-information/household-size/), this number directly sets your [ACA income limits](/aca-income-limits) and [Medicaid income limits](/medicaid-income-limits).
ACA Household vs. Medicaid Household: Key Differences
The ACA treats the entire tax return as one household. Non-applicant dependents and a non-enrolling spouse still count toward the total. Married couples must file jointly to receive premium tax credits; three narrow exceptions exist (domestic violence, abandoned spouse, head-of-household). Medicaid applies the starting point person by person. A pregnant person adds one to their own count per expected baby, raising the income threshold.
ACA vs. Medicaid household rules (2026 comparison)| Rule | ACA / Premium Tax Credit | MAGI Medicaid |
|---|
| Base unit | One count per tax return | Separate count per member |
| Spouse | Always included if filing jointly | Included if living together |
| Dependents | All claimed dependents | Match tax filer's household |
| Pregnancy | Not adjusted | Count as +1 per expected baby |
Source: HealthCare.gov household guidance; Medicaid MAGI rules (42 CFR 435.603).
Source: https://www.healthcare.gov/income-and-household-information/household-size/
Frequently Asked Questions
Does a non-dependent adult child count in my household for ACA subsidies?
No. An adult child who files their own tax return is not your dependent, so they form a separate one-person household for [ACA income limits](/aca-income-limits). They can still enroll on your plan up to age 26, but their subsidy eligibility is calculated on their own income and household size, not yours.
How does household size affect the income threshold I must meet?
A larger household size raises the dollar amount at each Federal Poverty Level percentage. In 2026, 100% FPL for a household of 1 is $15,960; for a household of 4 it is $33,000. A family of 4 can earn more and still qualify for Medicaid at 138% FPL or ACA subsidies. Full chart: [Federal Poverty Level](/federal-poverty-level).
I am pregnant. Does my unborn baby count in my household size for Medicaid?
Yes, for Medicaid. A pregnant person counts as themselves plus the number of babies expected. So a single pregnant woman expecting one baby is a household of 2 for MAGI Medicaid purposes in 2026. This raises her income threshold and can make her eligible at a higher income. ACA does not adjust household size for pregnancy.
