The one-line difference
An HMO (Health Maintenance Organization) trades flexibility for price. A PPO (Preferred Provider Organization) trades price for flexibility. Everything else — referrals, out-of-network billing, how hard it is to keep a specialist — follows from that single trade.
CMS groups Marketplace plans into four network types: HMO, PPO, EPO and POS. Most shoppers only ever see HMO and PPO on the shelf, because those two dominate individual-market filings in the majority of counties, but it is worth checking whether the other two appear in yours.
The four plan types side by side
Network type tells you who you can see and what happens when you go outside the list. It says nothing about the metal tier, which is a separate axis controlling how costs are split.
| Plan type | Referral needed? | Out-of-network cover | Typical premium |
|---|---|---|---|
| HMO | Usually yes | Emergencies only | Lowest |
| EPO | Usually no | Emergencies only | Low to mid |
| POS | Usually yes | Partial, at a higher cost share | Mid |
| PPO | No | Yes, at a higher cost share | Highest |
Monthly premium versus total annual cost
The premium is what you pay every month whether or not you see a doctor. The deductible is what you pay for care before the plan starts sharing costs. Coinsurance is the percentage you keep paying after the deductible. The out-of-pocket maximum is the ceiling: once you hit it, the plan pays 100% of covered in-network care for the rest of the plan year.
HMOs typically win on premium. PPOs often win when you actually use a lot of care, particularly outside a narrow network. The only honest way to compare is to model the whole year rather than the monthly bill.
A useful test: add twelve monthly premiums to the care you realistically expect to use, capped at the out-of-pocket maximum. Run it twice — once for a healthy year, once for a bad year. If the HMO wins both, take the HMO. If the PPO wins the bad year by more than the HMO wins the good year, the PPO is buying you real insurance rather than convenience.
Worked example: the same household, two plans
Take a 42-year-old with one recurring specialist visit a quarter and one prescription. Assume an HMO at $340 a month with a $4,500 deductible, and a PPO at $505 a month with a $2,800 deductible.
In a quiet year the HMO costs roughly $4,080 in premiums plus a few hundred in copays; the PPO costs about $6,060 in premiums plus lower copays. The HMO wins comfortably.
In a year with a surgery that pushes both plans to their out-of-pocket maximum, the gap narrows sharply and can invert, because the PPO's lower deductible and maximum are reached faster. If the specialist you rely on is out of the HMO's network, the HMO's number is not $4,080 at all — it is $4,080 plus the entire uncovered bill, because out-of-network care generally does not count toward an HMO's cap.
These figures are illustrative. Actual premiums are filed county by county and depend on your ZIP code, age, tobacco use and household — which is exactly why this site does not display live prices.
Networks and referrals in practice
HMO plans require a primary care physician who coordinates your care and issues referrals. Out-of-network care is generally not covered except in emergencies, and federal surprise-billing protections cover emergency and certain ancillary situations rather than routine elective care with an out-of-network provider.
PPO plans let you book a specialist directly and reimburse a share of out-of-network bills, though at a lower rate than in-network care and often against an 'allowed amount' rather than the provider's actual charge.
Before you enroll, check each doctor and each hospital individually on the carrier's own directory for the specific plan, not the carrier in general. Carriers commonly sell several networks under one brand, and a doctor who takes the carrier's employer plan may not take its Marketplace plan.
How metal tiers interact with network type
Metal tier — Bronze, Silver, Gold, Platinum — sets the split between premium and cost sharing, not the network. A Bronze HMO and a Gold HMO can share the same doctors and behave completely differently at the till.
One rule matters more than most people realise: cost-sharing reductions, which cut deductibles and out-of-pocket maximums for eligible lower-income households, are only available on Silver plans. If you qualify, a Silver plan can end up both cheaper and richer than the Bronze plan sitting next to it.
Who each plan type actually suits
Pick an HMO if you live and receive care in one metro area, are happy to route through a primary care physician, and want the lowest predictable monthly cost.
Pick a PPO if you split time between states, have a specialist or academic medical centre you will not give up, travel frequently for work, or have a condition where continuity of a specific care team matters more than the monthly saving.
Pick an EPO if you want PPO-style direct specialist access at closer to HMO pricing and can live inside a fixed network. Pick a POS if you want an HMO's price with a partial escape hatch for out-of-network care.
How to check this for your own ZIP code
Plan availability is set at county level. Two neighbouring counties in the same state can have different carriers, different networks and different prices for identical coverage.
Confirm what is actually on the shelf for you at HealthCare.gov or your state Marketplace, then verify each provider in the carrier's directory for that exact plan. If you want a shortcut, Amy will narrow the plan structures worth looking at in about 90 seconds and hand you to a licensed broker who can quote binding prices.
