Open Enrollment Guide, How to Choose Your Employer Health Plan

What is open enrollment?

Open enrollment is the annual window when you can sign up for a new employer health plan, switch plans, add or drop dependents, or change your FSA or HSA elections. Outside of this window, you generally cannot make changes unless you experience a qualifying life eventA change in your life or household (marriage, birth, job loss, move, etc.) that opens a limited special enrollment period to change health coverage outside the annual open enrollment window. like marriage, having a child, or losing other coverage.

When does open enrollment happen?

For most employers, open enrollment runs for two to four weeks between October and December, with new coverage starting January 1. Exact dates vary, and your HR department or benefits portal will list your company's window. Mark the deadline on your calendar: missing it typically locks in your existing plan for another year.

What plan details should I compare?

For every plan you are considering, gather these numbers from the Summary of BenefitsA standardized 4 to 8 page document every health plan must provide, summarizing premiums, deductible, out-of-pocket max, covered services, and three required coverage examples for plan-to-plan comparison. document:

• PremiumFixed amount, taken from each paycheck. You pay these no matter how much care you use. per paycheck and number of paychecks per year
• DeductibleThe amount of medical bills you need to pay in a year before insurance starts splitting the bills with you. (individual and family)
• Out-of-pocket maxThe most you pay for covered medical bills in a year. After this, insurance pays 100% of covered costs. (individual and family)
• CopayA fixed dollar amount you pay for certain services (like office visits or prescriptions). Copay plans often have higher premiums but lower costs for routine care. Copays usually do not count toward your deductible, but they typically count toward your out-of-pocket maximum. amounts for office visits, specialist visits, and prescriptions
• Coinsurance percentAfter you reach your deductible, this is the percent of each bill you pay while insurance pays the remainder. after the deductible
• Network typeHMOs often need referrals and in-network care. EPOs stay in-network without referrals. PPOs allow broader access. (HMO, EPO, or PPO) and whether your doctors are in-network
• Whether the plan is HSATypically paired with high-deductible plans. Contributions are pre-tax, roll over yearly, and can be invested.-eligible, and any employer HSA contribution

For deeper context on each number, see deductible vs out-of-pocket max, copay vs coinsurance, and HMO vs PPO vs EPO.

How do I calculate total annual cost?

Total annual cost = annual premiums + expected out-of-pocket spending under the plan. To estimate the out-of-pocket portion, think about a realistic year of care: routine visits, prescriptions, and any planned procedures. Then think about a worst-case year that hits the out-of-pocket max. Both numbers matter.

A plan with $50 lower premiums per paycheck saves $1,300 per year over 26 paychecks. That can be wiped out by a deductible that is $2,000 higher in a year with an unexpected procedure. The right comparison is total annual cost across multiple usage scenarios, not premium alone.

What is the biggest mistake during open enrollment?

The most common mistake is comparing premiums alone. The premium is the only cost that is visible every paycheck, so it feels like the main number. The deductible, out-of-pocket max, and network type often matter more in the years when you actually need care. A close second mistake is rolling over the same plan year after year without checking whether something better is now offered.

Open enrollment checklist

A six-step process for picking the right plan:

1. Gather your plan options

   Download the Summary of Benefits for every plan offered. Note premiums per paycheck, deductible, out-of-pocket max, copays, coinsurance, and any employer HSA or HRA contribution.

2. Estimate your healthcare usage

   List expected medical events for the year: primary care visits, specialist visits, prescriptions, planned procedures, and any chronic conditions. Be realistic about a low-usage and a high-usage scenario.

3. Verify your doctors are in-network

   Check each plan's provider directory and call your providers' offices to confirm. Out-of-network costs can dramatically increase your total spend.

4. Calculate total annual cost for each plan

   Add 12 months of premiums to your estimated out-of-pocket spending under each plan. Compare the totals, not the premiums or deductibles alone.

5. Factor in tax-advantaged accounts

   If an HSA-eligible plan is offered, account for employer HSA contributions and the tax savings on your own contributions. If only traditional plans are offered, decide whether a Health FSA makes sense for your predictable expenses.

6. Enroll before the deadline

   Submit your election through your employer's benefits portal before the deadline. Missing the window typically locks in your previous plan for another year.

Compare your plan options now

The Health Plan Compare calculator lets you enter the details for two or three employer plans and see total annual cost across low, medium, and high usage scenarios. It is the fastest way to make the comparison this guide describes.

Related guides

• Deductible vs out-of-pocket max
• Copay vs coinsurance
• HSA vs PPO total annual cost
• HMO vs PPO vs EPO
• FSA vs HSA
• Health insurance glossary