If you miss open enrollment, you generally cannot buy a health insurance plan through the marketplace or your employer until the next enrollment period. That means you could spend months without coverage, exposed to the full cost of any medical care you need. The average three-day hospital stay costs around $30,000, and without insurance, you’re responsible for the entire bill. The good news: several backup options exist depending on your circumstances.
When Open Enrollment Ends
For marketplace (ACA) plans, open enrollment runs from November 1 through January 15. If you enroll by December 15, your coverage starts January 1. If you sign up between December 16 and January 15, coverage begins February 1. After January 15, the marketplace closes to new applicants unless you qualify for a special exception.
Employer-sponsored plans follow their own schedule, which varies by company. Most employers run enrollment in the fall, but some align it with their fiscal year. If you miss your employer’s window, the same basic rule applies: you’ll need a qualifying reason to enroll outside of it.
Qualifying Life Events That Reopen Enrollment
A Special Enrollment Period (SEP) lets you sign up for coverage outside the normal window if something significant changes in your life. You typically get 60 days from the event to enroll in a marketplace plan. Employer plans must offer at least 30 days. The qualifying events fall into four categories.
Losing existing coverage is the most common trigger. This includes being laid off or leaving a job, aging off a parent’s plan at 26, or losing eligibility for Medicaid or CHIP. Voluntarily dropping your plan doesn’t count.
Household changes include getting married, getting divorced, having a baby, or adopting a child. A death in the family also qualifies. If you just missed enrollment and happen to be getting married soon, that wedding opens a new enrollment window for both marketplace and employer plans.
Moving to a new ZIP code or county triggers a SEP because the plans available to you change by location. This applies to relocating for any reason, including students moving for school and seasonal workers.
Other events that qualify include becoming a U.S. citizen, leaving incarceration, gaining membership in a federally recognized tribe, and starting or ending AmeriCorps service.
If none of these apply to you right now, keep them in mind. A move or job change in the coming months could open a window you weren’t expecting.
Medicaid and CHIP Have No Enrollment Deadline
Medicaid and the Children’s Health Insurance Program (CHIP) accept applications year-round with no enrollment window to miss. If your income is low enough, you can sign up any day of the year and get coverage immediately. Eligibility rules vary by state. Some states cover all adults with household incomes below a certain threshold, while others have narrower criteria focused on children, pregnant individuals, and people with disabilities.
Even if you’re unsure whether you qualify, it’s worth applying. Many people who assume they earn too much are surprised to find they’re eligible, particularly if they have children or are pregnant.
Short-Term Plans: A Temporary Bridge
Short-term health insurance plans can be purchased at any time and don’t follow open enrollment rules. Under current federal regulations, these plans last a maximum of three months, with total coverage (including renewals) capped at four months within a 12-month period.
These plans are cheaper than marketplace coverage, but the tradeoffs are significant. They can deny you for pre-existing conditions, exclude mental health care, skip prescription coverage, and impose annual or lifetime benefit caps. They don’t count as minimum essential coverage under state mandates. Think of them as emergency-only protection, not a substitute for comprehensive insurance. If you’re healthy and just need something to cover a catastrophic accident for a few months until the next enrollment period, they serve that narrow purpose.
State Penalties for Going Uninsured
The federal tax penalty for lacking health insurance was reduced to $0 in 2019, so most Americans won’t owe anything to the IRS for a coverage gap. However, a handful of states enforce their own mandates. Massachusetts has had an individual mandate since 2006. New Jersey, the District of Columbia, and Vermont have also enacted mandate laws. If you live in one of these places and go without qualifying coverage, you’ll face a state tax penalty when you file your return.
Medicare Has Steeper Consequences
If you’re 65 or older (or otherwise Medicare-eligible), missing your enrollment window carries a penalty that lasts for the rest of your life. For Part B, which covers doctor visits and outpatient care, your premium increases by 10% for every full year you were eligible but didn’t sign up. If you waited three years, you’d pay 30% more on every monthly premium for as long as you have Part B.
Part D (prescription drug coverage) works similarly but compounds faster. You’ll pay an extra 1% of the standard premium for every month you went without creditable drug coverage after first becoming eligible. That adds up to 12% per year, and like the Part B penalty, it’s permanent. These penalties are designed to discourage people from waiting until they get sick to enroll, and they make delaying Medicare enrollment one of the costliest insurance mistakes you can make.
What to Do Right Now
If you’ve missed open enrollment and don’t have a qualifying life event on the horizon, your immediate options depend on your income and situation. Start by checking whether you qualify for Medicaid, since there’s no deadline and coverage can begin right away. If your income is too high for Medicaid, look at whether any life event in the next few months (a move, a marriage, a job change) might trigger a Special Enrollment Period. In the meantime, a short-term plan can provide basic catastrophic protection for up to four months.
If you missed your employer’s enrollment period specifically, contact your HR department. Some companies allow late enrollment for employees who can demonstrate a qualifying life event, and HR staff can tell you exactly which events your company’s plan recognizes and what documentation you’ll need. Employer plans are required to offer a Special Enrollment Period of at least 30 days following a qualifying event, so the door isn’t necessarily closed.
For marketplace coverage, mark your calendar for November 1, when the next open enrollment begins. Enrolling by December 15 gets you coverage starting January 1, the earliest possible start date. Setting a reminder now is the simplest way to avoid the same problem next year.