The short answer
Marketplace health plans can normally be bought only during open enrollment each fall, but a major life event can open a Special Enrollment Period at other times. The common qualifying events are losing other health coverage, getting married, having or adopting a child, and moving to a new area, along with a few others such as gaining citizenship or being released from incarceration. In most cases you have 60 days from the event to pick a plan, and for a coverage loss you know is coming you can start up to 60 days before. People who lose Medicaid or CHIP may have 90 days. Coverage usually starts the first of the month after you choose a plan, but for a birth or adoption it can be backdated to the day of the event. The monthly window for people with income at or below 150 percent of the poverty line ended in August 2025. Medicaid and CHIP accept applications all year.
The clock for each event
Open enrollment runs each fall, starting November 1, for coverage the following year; the closing date depends on whether your state uses HealthCare.gov or its own Marketplace. Outside it, you need a special enrollment period, and the timing depends on what happened:
Swipe sideways to see the whole table.
| Event | Time to choose a plan | When coverage can start |
|---|---|---|
| Losing job-based or other coverage | Up to 60 days before or after the loss | The day after the old coverage ends, if you enroll beforehand |
| Losing Medicaid or CHIP | Up to 90 days after | The first of the month after you choose a plan |
| A birth, adoption or foster placement | 60 days after | The day of the event |
| Getting married | 60 days after | The first of the month after you choose a plan |
| Moving to a new ZIP code or county | 60 days after | The first of the month after you choose a plan |
For moves, you generally must have had qualifying coverage for at least one day in the 60 days before moving, with exceptions for people moving from another country or a U.S. territory. A move within the same ZIP code and county does not open a window, because the plans available to you have not changed.
Whatever the event, the safest habit is the same: apply as soon as you can, not on the 59th day, so there is time to fix a problem with documents or a plan choice.
What missing it costs
If the window closes, you generally wait for the next open enrollment, which can mean months without coverage. An emergency room visit or a hospital stay in that gap is billed in full, and even a routine prescription costs the cash price. That is why the date of the event matters more than the date you get around to dealing with it, and why the one window you can open early, before a known loss of coverage, is worth using.
Which events count, and which do not
- Losing qualifying coverage: job-based coverage, a Marketplace plan, Medicaid or CHIP, or a parent's plan at 26.
- Household changes: marriage, a birth, an adoption or a foster placement. Divorce or a death qualifies only if it costs you coverage.
- Moves: to a new ZIP code or county, to the United States, or to or from student or seasonal housing, with the prior-coverage condition above.
- Other events: gaining citizenship or lawful presence, release from incarceration, leaving AmeriCorps service, or gaining access to an individual coverage arrangement from an employer.
- Exceptional circumstances: a serious illness, a natural disaster, or an error by the Marketplace or an assister that kept you from enrolling.
Losing coverage because you did not pay premiums, or dropping it voluntarily, generally does not qualify. Neither does moving only for medical treatment or a vacation.
Use the window before a loss
When you know coverage will end, such as when a job is ending, you can enroll up to 60 days before the loss so the new plan starts the day after the old one ends. Picture someone laid off on June 10 whose job-based coverage ends June 30. Applying in mid-June, reporting the coming loss and choosing a plan before June 30 means coverage from July 1, with no gap, and because income has dropped, likely a larger premium tax credit.
If you are offered COBRA after a job loss, you can choose a Marketplace plan instead during this window. Dropping COBRA later in the year does not open a new window unless another event occurs, so compare the two before you decide. Estimate your Marketplace subsidy at your new income to see the difference; our guide to Marketplace subsidies explains how the credit works.
A new baby, step by step
A birth is the one event where coverage can reach backward, which takes some of the pressure off the first exhausting weeks. Still, the clock is running.
- Apply for the baby's Social Security number at the hospital; it makes every later step easier.
- If the baby's mother is covered by Medicaid or CHIP, the baby is generally covered for the first year; confirm it with the state agency.
- If you have a job-based plan, tell the benefits office within its window, usually 30 days.
- For Marketplace coverage, add the baby or choose a new plan within 60 days. Coverage can start on the day of birth, so the hospital bills for the delivery and newborn care can be covered.
If a parent's income changed around the birth, update it at the same time, since the household's size and income both affect the premium tax credit.
A window that closed in 2025
From 2022 until August 2025, people with household income at or below 150 percent of the poverty line could enroll in a Marketplace plan in any month. CMS ended that window effective August 25, 2025, and income alone is no longer treated as an exceptional circumstance.
People with low incomes can still enroll during open enrollment or after any qualifying event, and Medicaid and CHIP take applications all year. If your income is near or below the poverty line, check Medicaid first; in a state that expanded it, you may qualify without waiting for any window.
If you already have a Marketplace plan
Some events let you add someone or change plans mid-year. A new spouse or baby can be added, or the household can move to a new plan; for some events, people already enrolled can change only to a plan in the same metal level, such as from one silver plan to another.
A change in income does not usually let you change plans, but it does change your premium tax credit. Report it within 30 days so your monthly credit is adjusted and you avoid a large repayment at tax time. In some cases a change in eligibility for the credit can itself open a window to switch.
Proving the event, on time
You may be asked for documents confirming the event: a letter from a former employer or insurer showing when coverage ended, a marriage or birth certificate, or a lease or utility bill showing a new address. The request has its own deadline, and missing it can cancel the plan you just chose. Keep a record of the date of the event and the date you applied. If an error or emergency kept you from enrolling on time, explain it and ask about an exceptional circumstances period.
Job-based plans and Medicare run their own clocks
If you can join a job-based plan, through your own job or a spouse's, that plan has its own special enrollment rights: generally 30 days after events such as marriage, a birth or losing other coverage, and 60 days after losing Medicaid or CHIP. Ask the employer's benefits office, and ask early, since the shorter window is easy to miss.
Medicare has separate enrollment periods with their own deadlines and penalties, explained in Medicare sign-up deadlines. If you are turning 65, do not rely on a Marketplace window.
Rules that can change
The list of qualifying events and the rules for proof are set by CMS and may change, and state-run Marketplaces can offer extra windows that HealthCare.gov does not. Our calculator estimates your expected contribution, not whether you qualify to enroll.
Official sources
On the day of the event
Write down the date, because the clock starts there. If coverage is ending, apply before it ends; if a baby has arrived, add the baby within 60 days; if your income has fallen sharply, check Medicaid as well, since it has no window at all. Then keep every document that proves the date.
