How to Use the Employer vs. ACA Health Plan Calculator
Comparing your employer's health plan against an ACA marketplace plan isn't just about the sticker price of the premium — it comes down to total cost, which combines what you pay every month with what you'll owe out of pocket based on how much care you actually use. A marketplace plan with a lower premium (especially with a subsidy) often has a higher coinsurance rate, so it can end up cheaper for light healthcare users but more expensive for people with ongoing medical needs. This calculator adds each plan's annual premium to your expected medical costs multiplied by that plan's coinsurance rate, then compares the two totals.
For example, with $200 in expected monthly medical costs, a $350 employer premium at 20% coinsurance, and a $180 ACA premium at 30% coinsurance, the employer plan costs about $4,680 a year while the ACA plan costs about $2,880 — a savings of roughly $1,800 by switching. That gap narrows or reverses as your expected medical costs increase, since the higher-coinsurance plan's costs grow faster.
This is a simplified comparison that doesn't account for deductibles, out-of-pocket maximums, network differences, or losing employer contributions to an HSA. Before switching off an employer plan, also check ACA open enrollment timing and whether you'd qualify for a special enrollment period, since you generally can't switch outside of those windows.
Frequently Asked Questions
If your employer plan's monthly premium share is high relative to your medical usage, a lower-premium ACA marketplace plan, especially with a subsidy, can cost less overall even if its coinsurance rate is a bit higher. The comparison depends heavily on how much healthcare you actually use in a year.
No. If you expect high medical expenses, a plan with a lower coinsurance rate, even at a higher premium, often costs less overall because your out-of-pocket share of a larger medical bill matters more than the premium difference. Compare both plans using your own expected usage before switching.