The Affordable Care Act’s next open enrollment period begins November 1, and it arrives with the steepest round of proposed premium increases insurers have filed in nearly a decade. Enrollees who buy their own coverage through HealthCare.gov or a state marketplace will have from November 1 through January 15 to pick a 2027 plan, according to the federal marketplace’s own published schedule. That window survived a fight over whether it would be cut short. The dates matter this year specifically because the plans behind them cost more, and the enrollment calendar decides how much time shoppers get to react.
The Nov. 1-Jan. 15 Calendar, Confirmed by HealthCare.gov
Enrollment for next year’s Affordable Care Act coverage does not begin on a floating date set by each insurer; it opens on a fixed federal date that applies to the federal marketplace and most state-run exchanges alike. That date is November 1, and it starts a clock that determines how quickly a plan selected today can take effect.
HealthCare.gov lists November 1 as the first day enrollees can shop, renew, or switch plans for 2027 coverage, with the window running through January 15. Enrolling by December 15 locks in coverage that starts January 1; anyone who waits past that date but still enrolls by January 15 starts coverage on February 1 instead.
Missing the January 15 cutoff removes most people from the marketplace until the following November, absent a qualifying life event such as a move, a marriage, or the loss of other coverage. A Special Enrollment Period covers those situations, but it is not a substitute for the general window, and it requires documentation the standard enrollment period does not. People who miss the deadline and later discover a qualifying event, rather than simply forgetting to enroll, are the ones a Special Enrollment Period is built for; it is not a general grace period for anyone who misses the calendar.
Free download: IRMAA, the Medicare Savings Programs and Extra Help explained side by side, with the official form and contact for each. Get the free Medicare premium route finder.
A Rule That Would Have Cut the Window in Half
The current schedule was not guaranteed to survive. A 2025 federal rule set out to shorten open enrollment starting in 2027, and the Congressional Budget Office described the change directly in a budget analysis: the rule would have limited enrollment to a nine-week window between November 1 and December 31, instead of the longer stretch running to January 15.
CBO’s own estimate of that shortened window found it would reduce the number of people with marketplace coverage, since a shorter window gives procrastinators, people juggling paperwork, and people who miss a renewal notice less time to act before losing the chance to enroll for a full year. The rule was challenged, and the enrollment period in effect for 2027 runs to January 15, matching the traditional calendar instead of the shortened one.
That distinction is not cosmetic. A household that assumes the shorter window is in effect could stop shopping in mid-December, losing weeks it still has to compare plans, switch away from an insurer that dropped a doctor’s network, or move to a different metal tier as prices shift.
The same rule that proposed the shorter enrollment window also proposed ending an automatic 60-day extension for resolving income discrepancies flagged on an application, and it would have let insurers require enrollees who switch plans to pay off past-due premiums before new coverage could start. All three provisions were tied to the same 2025 rule, so the enrollment window, the verification grace period, and the switching rules reverted together rather than as separate, unrelated fights.
Why This Year’s Prices Make the Extra Weeks Matter More
The extended window lands on top of what KFF’s Health System Tracker counts as the second-highest proposed rate increase since 2018. Across 276 insurers filing in all 50 states and Washington, D.C., the median proposed 2027 premium increase is 15%, following an 18% median proposal the year before that was finalized even higher.
Insurers point to rising medical costs, GLP-1 drug spending, and a sicker remaining risk pool as the enhanced premium tax credits that lapsed at the end of 2025 push healthier, unsubsidized enrollees out of the market. Those factors do not move evenly across insurers: some filed increases in the single digits, while more than four dozen nationally proposed increases above 25%.
State-run marketplaces are not required to match the federal calendar exactly. Some, including California and New York, have historically kept their own enrollment windows open longer than HealthCare.gov’s, so a resident of one of those states should confirm the date on their state’s own exchange rather than assume the federal January 15 deadline applies to their plan.
The preliminary filings KFF compiled can still change before state regulators finalize 2027 rates later this year, which is itself an argument for using the full enrollment window rather than the shortened one that nearly took effect. Plans and prices posted on November 1 are not guaranteed to be the last word by January 15. Shoppers who compare plans early and again closer to the January 15 deadline have a better chance of catching a rate correction, a new insurer entering their county, or a network change than someone who enrolls once on November 1 and never returns to the marketplace before the window closes.
The Forms Open Enrollment Doesn’t Hand Out
Open enrollment gives ACA marketplace shoppers a calendar and a set of prices, but it does not flag the separate Medicare programs that help pay premiums, drug costs, and copays for people who age into Medicare on a fixed income. Those programs run on their own forms and their own income limits, and open enrollment’s November 1 date has nothing to do with them.
The Medicare Cost & Coverage Protection Kit is a 10-page kit built around 51 state Medicare cost-help packs and the new Part D out-of-pocket cap, plus the prior-authorization appeal steps and a medication and cost tracker.
Look up the state-specific Medicare cost-help programs in The Medicare Cost & Coverage Protection Kit.
This article was researched and drafted with the assistance of AI and reviewed by The Money Overview editorial team.
