How to Choose a Health Plan During Open Enrollment

The dates that decide everything

Marketplace open enrollment for 2027 coverage runs November 1, 2026 through January 15, 2027 on HealthCare.gov, and December 15, 2026 is the deadline for coverage starting January 1, 2027. Enroll between December 16 and January 15 and coverage starts February 1, which leaves January uncovered. Employer open enrollment runs on a different calendar, usually a two to four week window in October or November, and the deadline is whatever your employer sets, not the marketplace date. Put both dates on the calendar now, because missing the window generally means waiting until next fall unless a qualifying life event opens a special enrollment period.

The 2027 season carries a trap that did not exist in recent years. The enhanced premium tax credits that expanded marketplace subsidies from 2021 through 2025 expired on December 31, 2025. Households that qualified for extra help before may pay more now even on the same plan, because the credit itself reverted to the pre-2021 income limits. KFF's analysis of insurer filings found a median proposed premium increase of 15% for 2027 marketplace plans on top of that. The combination means last year's plan, renewed automatically, can arrive in January with a substantially larger bill. Automatic renewal is convenient and, this year, it is the most expensive default on the enrollment page.

Step one: gather your numbers before you compare

Open last year's explanations of benefits and add up the billed charges, not what you paid. Billed charges are the input the calculator needs, because the deductible and coinsurance apply to charges. Note any planned care for next year: a surgery, a pregnancy, a new prescription, a child starting regular therapy. Then list your doctors and your prescriptions, because a plan that wins on arithmetic and excludes your doctor has not won. Check the provider directory and the drug formulary for each plan you are considering, not just the premium page.

While you are gathering, note your plan's out-of-pocket maximum and whether your employer contributes to a Health Savings Account or a Health Reimbursement Arrangement. An employer HSA seed of $500 or $1,000 is real money that belongs in the comparison: it reduces the effective cost of the high-deductible plan dollar for dollar. Many shoppers compare premiums and deductibles and forget the employer contribution entirely, which systematically biases the choice against the high-deductible plan that their employer is subsidizing.

Step two: price both plans at three bill levels

Enter both plans in the calculator: monthly premium share, deductible, coinsurance, and out-of-pocket maximum. Price them at your best guess for billed charges, at half that guess, and at double it. Read the break-even bill amount, the amount where the two plans cost the same. If one plan wins all three scenarios, the choice is made. If the winner flips, weight the worst case more heavily than the typical case when your emergency fund is thin, because the worst case is the scenario that breaks a household budget.

Worked example from the calculator defaults: Plan A at $250 a month with a $4,000 deductible against Plan B at $400 a month with a $1,000 deductible, both at 20% coinsurance. At $800 in bills, Plan A wins by $1,800. At $3,500 in bills, Plan B wins by $200. At $12,000 in bills, Plan B wins by $600. The break-even is $3,250. A household expecting a quiet year takes Plan A; a household expecting a surgery takes Plan B; a household that genuinely does not know should weigh the worst case, where Plan B wins by $2,200, against the light year, where Plan A wins by $1,800, and decide which mistake it can afford.

Step three: check the four things arithmetic cannot see

First, the network. Is your primary care doctor, your specialist, and your hospital in network on both plans? Out-of-network charges do not count toward the out-of-pocket maximum the same way, and a single out-of-network surgery can dwarf any premium saving. Second, the drug list. Is each prescription covered, and at what tier? A drug that moves from tier two to tier four can cost more per month than the premium gap between plans. Third, the HSA question. Does the low-premium plan qualify as a high-deductible health plan under the IRS rules, and does your employer seed the account? Fourth, the income question for marketplace shoppers: have you updated your projected income, since the credit now follows the pre-2021 limits and a raise can move a household over a threshold?

Fifth, and this one is free: the dental and vision check. Medical open enrollment is not dental open enrollment, and households that bundle the decisions often discover in February that the dental plan they assumed renewed did not. It is a small check, but it belongs on the same checklist because the same window closes on it.

Step four: decide, enroll, and file the proof

Enroll before the deadline that gives you January 1 coverage: December 15 for the marketplace, your employer's stated deadline for employer coverage. Save the confirmation, the plan summary, and the premium notice. If you buy on the marketplace, confirm that the premium tax credit applied matches your updated income estimate, and set a reminder to update it if your income changes during the year, because a credit based on stale income gets reconciled at tax time. If you chose the high-deductible plan, open the Health Savings Account before you need it, and confirm the employer contribution landed.

Then write down the decision for next year: which plan you picked, the break-even bill amount, and the bill level that would have flipped it. Next November, that note turns a fresh research project into a five-minute check. Open enrollment rewards households that keep records, because the plans change every year and memory does not. The checklist above is the whole job: dates, numbers, three scenarios, four blind spots, and a filed confirmation. Everything else on the enrollment portal is marketing.

Open enrollment questions

When is open enrollment for 2027 coverage?

November 1, 2026 through January 15, 2027 on HealthCare.gov. December 15, 2026 is the deadline for coverage starting January 1, 2027; enroll later and coverage starts February 1. Employer windows differ, usually in October or November.

Should I let my plan renew automatically?

Not for 2027 without checking it. The enhanced premium tax credits expired at the end of 2025, and KFF found a median proposed premium increase of 15% for 2027 marketplace plans. An unchecked renewal can cost substantially more than last year.

What should I check besides the premium?

Your doctors in network, your prescriptions on formulary, the out-of-pocket maximum, any employer HSA contribution, and your updated income for marketplace credits. Then price both plans at three bill levels in the calculator.

Keep reading

• Health Insurance Deductible vs PremiumThe break-even math at the center of the choice.
• Health Insurance Out-of-Pocket MaximumThe worst-case number to check before you enroll.
• How Much Does Health Insurance Cost?The KFF averages behind the 2027 increases.
• Health Insurance Cost CalculatorPrice both plans by total yearly cost, with the break-even bill amount.