On this page
Every open enrollment, people pick between a high-deductible plan with a low premium and a low-deductible plan with a high premium, and most of them decide by gut. The gut is wrong surprisingly often. There is a simple calculation that answers the question, and it takes about two minutes with your two actual quotes in front of you.
The trade you are making
A high-deductible plan charges you less every month and more when you need care. A low-deductible plan charges you more every month and less when you need care. Premiums are guaranteed spending. Deductibles are possible spending. The math is just a comparison of the guaranteed savings against the possible extra cost.
The break-even formula
Take the annual premium savings of the high-deductible plan and subtract it from the deductible difference. The result is roughly how much you would need to spend on care in a year before the low-deductible plan starts winning.
Break-even spending = (deductible difference) minus (annual premium savings)
Here is how it works with example numbers. Say the high-deductible plan costs $300 a month with a $3,000 deductible, and the low-deductible plan costs $400 a month with a $1,000 deductible. These are illustrative figures, so run the same steps with your own quotes.
| High-deductible plan | Low-deductible plan | |
|---|---|---|
| Annual premium | $3,600 | $4,800 |
| Deductible | $3,000 | $1,000 |
| Premium savings | $1,200 a year on the high-deductible plan | |
| Extra deductible exposure | $2,000 more on the high-deductible plan | |
The deductible difference is $2,000 and the premium savings are $1,200, so the break-even point is about $800 of medical spending. Spend less than $800 on care in the year and the high-deductible plan wins. Spend more and the low-deductible plan pulls ahead.
Three scenarios that show how it plays out
Take a healthy 30-year-old who gets an annual physical (free preventive care) and one urgent care visit. Total spending lands well under the break-even point, so the high-deductible plan saves the full $1,200 in premiums minus a small urgent care bill. Clear win for the high deductible.
Now a 45-year-old managing mild hypertension with quarterly labs and a daily generic prescription. Annual spending lands near or just past the break-even point, so the two plans come out close. This is where the HSA tips it: high-deductible plans can be paired with a health savings account, and the tax savings on contributions often decide a tie. See HSA vs FSA for how those accounts compare.
Now a family with a kid who needs an MRI and a specialist workup in the same year. Spending blows past the deductible on either plan, and past the deductible both plans typically charge coinsurance up to the out-of-pocket maximum. In a heavy-use year the low-deductible plan usually wins, because the extra premium was buying exactly this protection.
What the formula leaves out
The simple version ignores coinsurance, copays, and the out-of-pocket maximum, which all kick in past the deductible. It also ignores the HSA tax benefit, which only the high-deductible side gets. For a rough decision the formula is enough. For an exact one, plug both plans’ full cost-sharing details into the same comparison instead of just the deductibles.
One more thing the formula cannot capture: behavior. Some people with high deductibles delay care they should get, which is the real risk of the cheaper premium. If you know you will skip the doctor over a $200 bill, the low-deductible plan may be worth it for reasons no spreadsheet shows. How health insurance deductibles work covers the basics if you need a refresher before you run your numbers.
