Once a year, many people get a short window to choose a health plan, and most of us spend it the same way: glance at the monthly premium, pick the cheapest one or the one we had last year, and move on. It's an understandable shortcut. Plans are wrapped in jargon, the deadline is easy to forget, and the choice feels impossible to get right.

The trouble is that the premium is only one slice of what a plan costs you. A plan with a low monthly price can cost far more in a bad year, and a plan with a higher price can be the cheaper choice for someone who uses a lot of care. This guide walks through the pieces that actually decide your yearly cost and gives you a worksheet for comparing plans side by side.

The Four Numbers That Make Up Your Real Cost

Every plan, whatever it's called, comes down to a handful of numbers. Our health insurance jargon decoder defines each term in depth; here's how they combine.

  • The premium. What you pay every month just to have the plan, whether or not you see a doctor. If your plan comes through an employer, this is usually the amount taken from each paycheck.
  • The deductible. What you pay for covered care before the plan starts sharing the bill. Some services, such as routine preventive visits, are often covered before you reach it.
  • Cost sharing after the deductible. Copays (flat fees per visit) and coinsurance (a percentage of the bill) are what you pay once the plan starts helping.
  • The out-of-pocket maximum. The most you'd pay in a plan year for covered, in-network care. After you hit it, the plan pays covered costs in full. Premiums don't count toward it.

Your yearly cost lands between two bookends. The best case is that you barely use the plan, so you pay only your premiums. The worst case is that you hit the out-of-pocket maximum, so you pay your premiums plus that maximum. Comparing plans means comparing both bookends, not just the monthly number.

Why the Cheapest Premium Often Isn't the Cheapest Plan

Insurers price plans on a tradeoff. A plan that asks for less each month usually asks for more when you actually need care: a larger deductible, higher cost sharing, or a higher out-of-pocket maximum. A plan with a richer benefit asks for more each month and less at the doctor.

Neither is better in general. The question is which one fits your likely year. A healthy person with no regular prescriptions may come out ahead with the low-premium plan, saving money every month and accepting some risk. Someone managing a chronic condition, expecting a procedure, or planning a pregnancy will probably spend past a high deductible anyway, so a pricier plan with a lower deductible can cost less in total.

In profile, a person in a denim jacket sits on a wooden bench in a sunny office-park courtyard holding blank sheets of paper, a bicycle and a steel water bottle beside them
Open enrollment is a once-a-year decision, so it pays to make it deliberately rather than on the last day.

Estimate Your Likely Year, Honestly

You can't predict illness, but you can predict a surprising amount of your care. Before you compare plans, jot down what you used last year and what you already know is coming.

  • Regular care: How many primary-care and specialist visits did your household have? Any recurring therapy or physical therapy?
  • Prescriptions: Which medications do you take regularly, and how often? Our guide to prescription drug coverage explains why a drug's tier can matter as much as the plan's deductible.
  • Planned events: A surgery, a pregnancy, a new baby, orthodontics, a scheduled scan.
  • Household changes: A new dependent, a spouse changing jobs, a child aging off a parent's plan.

Be a little pessimistic. People tend to remember the year they were healthy and forget the urgent-care visit or the unexpected test. Planning for a moderately busy year protects you from choosing a plan built for a year that never comes.

A Worksheet for Comparing Plans Side by Side

For each plan you're considering, work through the same four steps, and write the results down so they sit next to each other.

  1. Add up the yearly premium. Monthly premium times twelve (or the per-paycheck amount times the number of paychecks). If an employer contributes, use only your share.
  2. Calculate the best case. That's the yearly premium alone, assuming you use only free preventive care.
  3. Calculate the expected case. Add the yearly premium to a rough estimate of what you'd pay for your likely care. For each expected service, apply the deductible, copay, or coinsurance in turn.
  4. Calculate the worst case. The yearly premium plus the out-of-pocket maximum.

Now look at the spread. If one plan costs less in the expected case and its worst case is a number you could survive, it's a strong pick. If a plan saves you a modest amount in the best case but leaves a worst case you couldn't cover, that cheap premium is hiding a risk. Your emergency cushion matters here: a high-deductible plan is much easier to live with if you have the money set aside, as covered in our emergency fund guide.

Check the Network Before You Fall for the Price

A plan's numbers only apply fully to in-network care, meaning doctors, hospitals, and labs that have agreed to the plan's rates. Going out of network can mean a much higher bill or no coverage at all, depending on the plan type.

Before you commit, look up the specific people and places you rely on: your primary doctor, any specialists, your usual hospital, the pharmacy you use. Plans also differ in how they work. Some require a referral to see a specialist, and some only cover out-of-network care in an emergency. A plan that looks like a bargain is a poor deal if your doctor isn't in it.

Don't Forget the Accounts Attached to the Plan

Some plans make you eligible for a tax-advantaged account for medical costs, and some employers add money to it. That contribution lowers the true cost of a higher-deductible plan, so count it. Our HSA vs. FSA comparison explains how the accounts differ and which plans qualify.

It's also worth checking the other benefits that sit beside your health coverage, such as whether you need separate dental and vision, which we weighed in our dental and vision guide.

Common Open-Enrollment Mistakes

  • Auto-renewing without looking. Premiums, networks, and drug lists change from year to year. A plan that was right last year may not be now.
  • Choosing on premium alone. As above, it's only one piece.
  • Ignoring your own life changes. A new job, a new baby, or a move can change which plan fits best.
  • Missing the deadline. In most cases you can't switch plans mid-year without a qualifying life event, so the window really is once a year.
  • Forgetting the whole household. If a spouse has coverage through their own job, compare both before you decide who covers whom.
The bottom lineDon't pick a health plan by its monthly premium. Estimate your likely care, then compare each plan's best case, expected case, and worst case, and confirm your doctors and prescriptions are covered. The right plan is the one whose worst case you could afford and whose expected case costs you least.

Set aside an hour before the deadline: gather last year's usage, pull up the plan details side by side, and run the four-step worksheet. That single hour is usually worth more than any discount you could find elsewhere on your bills all year.