Then if you’ve met your deductible the big question is if you have a coinsurance after the deductible is met and an out of pocket maximum.

If your coinsurance is 60% or 80% or whatever, you won’t be responsible for the full bill but only that percentage of it.

If you have no coinsurance (a no charge after deductible plan) the service should be covered 100%

If you have coinsurance you should have an out of pocket max, which once hit should end the coinsurance and make services covered 100%. OOP max is typically quite a bit higher than deductible, sometimes 5-7x as much, but not always. It’s plan specific.

If your employer pays 50% that is an arrangement they have worked out and the specifics will be tied to your companies contract. This could mean they would pay 50% of any bill (unlikely as this is not a fixed cost they can plan for. Maybe if you’re like a ceo or some shit) or it could mean that up to your deductible they’ll pay 50%.

Also keep in mind even if you’re in a “covered 100%” scenario there are some instances in which you would still get billed:

Differential vs contracted rates - if the hospital charges $5000 for your procedure but your insurance only pays $4600 the hospital can sometimes bill you for the difference. This is not always the case; some contracts require the servicer (doctor) to accept the contracted rates and not charge more. Most common reason you’d get a bill in the above 100% scenarios and also the reason the math might not work out in coinsurance scenarios. Eg in the above surgery example your bill would probably be $1320. It should be 920 as that is 20% of the $4600 paid, or even $1000 as that is 20% of the 5k billed, but you pay the 920 as 20% of what your insurance paid plus the $400 difference, so $1320

Out of network providers - these can often have a separate deductible and sometimes in hospitals a provider can be out of network even though the hospital itself is in network

Non covered services - if the procedure involves a service that isn’t covered (uncommon)

Billing errors: if a bill looks wrong contest it and if your insurance isn’t reimbursing providers properly complain to them. Sometimes a medical office gets your info wrong and assumes your deductible or coinsurance is active when it shouldn’t be. Sometimes your insurance makes similar mistakes.