Every fall, open enrollment hands you the same two-line menu — a PPO with higher premiums and lower cost sharing, and a high-deductible plan (HDHP) with lower premiums and an attached — and the break room fills with utilization anecdotes dressed up as analysis. One colleague's HDHP "saved him thousands"; another's "cost her a fortune the year of the appendectomy." Both stories are true and neither is advice. The plan choice is total-cost arithmetic, it takes about thirty minutes with your actual benefit summaries, and it changes answer depending on numbers specific to your household. Here is the calculation.
The decision is one formula, not a philosophy
For each plan on the menu, compute one number at three utilization levels:
Total annual cost = your premium share + expected out-of-pocket spending − tax value of HSA contributions − employer HSA contribution
Run it for a low year, an expected year, and a catastrophic year (everyone hits the out-of-pocket maximum). Then choose the plan that wins across the scenarios you actually face, weighting by how predictable your family's utilization is. That is the entire method; everything below is inputs.
The HDHP's advantage is not the lower premium — it is the HSA's tax exemption, and that advantage only exists to the extent you actually fund the account.
The 2026 numbers you need before you compute anything
All four HDHP/HSA figures below are set by Rev. Proc. 2025-19 for calendar year 2026.
| Item (2026) | Self-only | Family |
|---|---|---|
| HDHP minimum deductible | $1,700 | $3,400 |
| HDHP out-of-pocket maximum | $8,500 | $17,000 |
| HSA contribution limit | $4,400 | $8,750 |
| HSA catch-up (age 55+) | +$1,000 | +$1,000 per spouse, in that spouse's own HSA |
Two footnotes on the table. First, "high deductible" on the marketing page does not guarantee HSA eligibility — the plan must meet the minimum-deductible and maximum-out-of-pocket tests above, so confirm the Summary of Benefits and Coverage (SBC) says "HSA-qualified." Second, a separate federal ceiling applies to all non-grandfathered plans in 2026: no individual can be required to pay more than $10,600 out of pocket for in-network essential benefits, even inside family coverage (the family ACA limit is $21,200).
The tax value comes from the HSA's triple exemption: contributions are deductible, growth is untaxed, and withdrawals for qualified medical expenses are untaxed. Contributions made through payroll also skip Medicare tax — 1.45%, plus the 0.9% additional Medicare tax above $200,000 of wages, which most attendings pay. For a physician at a 35% federal with a 5% state tax, each payroll HSA dollar avoids roughly 42 cents of tax; call it 40% for clean arithmetic. On the full $8,750 family limit, that is about $3,500 per year. The mechanics live in the HSA basics guide; where the HSA sits in your overall savings order — near the top — is covered in the retirement account map.
A worked family case: the formula with real structure
Example calculation
Assumptions, stated explicitly: attending physician, household of four; marginal rates 35% federal + 5% state; HSA funded to the $8,750 family maximum by payroll (tax value ≈ 40% ≈ $3,500). Plan features are illustrative — substitute the numbers from your own SBCs.
- PPO: employee premium $720/month ($8,640/year); $1,000 family deductible, then 20% coinsurance; $6,000 out-of-pocket maximum.
- HDHP: employee premium $420/month ($5,040/year); $3,400 aggregate family deductible, then 10% coinsurance; $7,000 out-of-pocket maximum; employer contributes $1,500 to the HSA.
Scenario A — low year ($2,000 of allowed charges):
- PPO: $8,640 + $1,000 + 20% × $1,000 = $9,840
- HDHP: $5,040 + $2,000 − $3,500 − $1,500 = $2,040
Scenario B — moderate year ($9,000 of allowed charges):
- PPO: $8,640 + $1,000 + 20% × $8,000 = $11,240
- HDHP: $5,040 + $3,400 + 10% × $5,600 = $9,000; minus $3,500 and $1,500 = $4,000
Scenario C — catastrophic year (both plans reach out-of-pocket maximum):
- PPO: $8,640 + $6,000 = $14,640
- HDHP: $5,040 + $7,000 − $3,500 − $1,500 = $7,040
On this menu the HDHP wins all three scenarios — by $7,800, $7,240, and $7,600 — because the premium delta is wide ($3,600), the employer seeds the account, and the out-of-pocket maximums are close. When the worst case still favors the HDHP, the decision is over. There is a shortcut for spotting that condition:
Key insight
Compute the worst-case test first: (HDHP out-of-pocket maximum − PPO out-of-pocket maximum) − (premium savings + HSA tax value + employer contribution). In the case above: ($7,000 − $6,000) − ($3,600 + $3,500 + $1,500) = −$7,600. If the result is negative, the HDHP wins even in a hospitalization year and no scenario modeling is needed. If it is positive, that number is the true price of the HDHP's bad years — weigh it against the good years honestly.
The result is not universal, and the sensitivity matters: strip out the HSA funding (a resident's cash flow, for instance) and the HDHP's Scenario C advantage collapses from $7,600 to $2,600; shrink the premium delta to $100 per month and it goes negative. The formula, not this menu's conclusion, is the takeaway.
The embedded-deductible trap in family HDHPs
Family HDHPs come in two designs, and the SBC line that distinguishes them moves real money.
Aggregate deductible: the full $3,400+ family deductible must be met — by any combination of family members — before the plan pays for anyone. One child's $6,000 emergency appendectomy means you pay the entire family deductible, alone, on that one claim. The $1,700 self-only figure is irrelevant inside family coverage; no rule gives an individual member of a family HDHP a $1,700 deductible.
Embedded deductible: each member has an individual deductible inside the family one. Friendlier design — but for the plan to stay HSA-qualified in 2026, an embedded individual deductible cannot be below $3,400, the family minimum. A family plan advertising a $2,000 per-person deductible is not an HSA-qualified HDHP no matter what the brochure implies, and contributions made against it are excess contributions with their own cleanup cost.
The one true per-person backstop is the ACA cap noted earlier: no individual pays more than $10,600 out of pocket in-network in 2026, even under family coverage.
Important
Before you model Scenario B, find the SBC answer to one question: "Is there a per-person deductible inside family coverage, and what is it?" Aggregate versus embedded can shift a single-patient year by $1,700 or more, and it is the most commonly skipped line in the document.
When the PPO wins: predictable, high, recurring utilization
The HDHP loses the arithmetic in a specific and recognizable situation: you already know next year is expensive.
- A planned pregnancy. Delivery reliably drives spending to or past the deductible. When the premium delta is narrow, the PPO wins outright. Illustrative: premium delta $100/month ($1,200/year), no employer seed, cash flow allows only $3,000 of HSA funding (tax value ≈ $1,200); delivery-year out-of-pocket $3,500 on the PPO versus $6,800 on the HDHP. PPO total: premium + $3,500. HDHP total: premium − $1,200 + $6,800 − $1,200 = premium + $4,400. The PPO wins by $900 — before accounting for the smoother billing experience during a year with enough going on.
- Chronic, recurring care. Weekly psychotherapy, biologic infusions, a child in speech or occupational therapy — households like this hit Scenario B or C every single year, with probability near one. PPO copay structures often price that utilization below what HDHP coinsurance produces, year after year.
- An unfunded HSA. If cash flow will not let you actually contribute, the tax value in the formula is zero and half the HDHP case evaporates. Be honest about this input.
Note what this section is not: a different philosophy. It is the same formula with the scenario weights moved to where your household actually lives. And when the arithmetic lands close, break the tie on networks — confirm your hospital, your children's pediatrician, and any specialist you rely on are in-network under the plan you pick, because a plan that forces out-of-network care loses by more than any spreadsheet margin.
The spouse-FSA trap and the other eligibility landmines
HSA eligibility requires that you have no disqualifying non-HDHP coverage — and coverage you never think about counts.
The classic miss: your spouse elects a general-purpose health FSA at their employer. Under Rev. Rul. 2004-45, that FSA can reimburse your medical expenses simply because you are their spouse — which makes you covered by a non-HDHP plan and disallows your HSA contributions for the entire FSA plan year, even if no claim is ever filed for you. Grace periods and carryover balances can extend the taint into the following year. The fixes are simple if done during enrollment: the spouse elects a limited-purpose FSA (dental and vision only) if offered, or skips the FSA.
The same disqualification logic applies to enrollment in any part of Medicare (relevant late-career, and automatic with Social Security claiming), and to being covered as a dependent under a spouse's traditional plan "just as backup." Two plans that each look fine can combine into zero HSA eligibility.
Mid-year switches: eligibility is measured month by month
Kept brief, because the rules are mechanical. HSA eligibility is determined on the first day of each month, and your contribution limit prorates by twelfths for the months you qualify — a July 1 job change onto an HDHP supports 6/12 of the annual limit. The last-month rule offers an override: if you are eligible on December 1, you may contribute the full-year limit — but you must then remain eligible through December 31 of the following year (the testing period), or the extra contributions become taxable income plus a 10% additional tax. Use the last-month rule deliberately or not at all. Plan switches themselves happen at open enrollment or at qualifying life events; the HSA math simply follows the months of actual HDHP coverage.
Quick takeaway
The plan choice is annual and reversible, and the HSA balance you build is portable regardless. Do the thirty-minute arithmetic every open enrollment with that year's premiums, that year's family, and that year's known utilization — not last year's default box.
Common questions
We are planning a pregnancy next year. Does that automatically mean the PPO?
No — it means the moderate and catastrophic scenarios get probability near one, which usually helps the PPO but does not guarantee it. A wide premium delta plus a large employer HSA contribution can keep the HDHP ahead even in a delivery year, as in the worked case above. Run the formula, then check that your preferred obstetrician and hospital are in-network under whichever plan wins.
Can my spouse and I each contribute $8,750?
No. The family limit is $8,750 total across both spouses' HSAs, split however you choose. The exception is the catch-up: each spouse who is 55 or older can add $1,000, but only into an HSA in that spouse's own name.
Is the HDHP irresponsible if we do not have a big emergency fund?
The out-of-pocket maximum is the real exposure, so ask the question concretely: if a $7,000 bill arrived this year, would it go on a credit card? If yes, the PPO's smoother cost structure has genuine value the spreadsheet does not capture. Note that the HSA balance itself can pay current bills tax-free — although paying cash and letting the account compound is the stronger long-run play, as covered in HSA strategies for physicians.
What happens to our HSA if we switch back to the PPO next year?
Nothing bad. The account is yours permanently: it keeps growing, it still reimburses qualified expenses tax-free, and it still works as the stealth retirement account described in the HSA basics guide. You simply cannot make new contributions for the months you are not HDHP-covered.
What to do next
- Pull the SBC for every plan on your menu and copy out five numbers each: your premium share, deductible, aggregate-or-embedded design, out-of-pocket maximum, and any employer HSA contribution. Free, fifteen minutes.
- Tally your family's last two years of actual claims from the insurer portal — that history is your "expected" scenario, and it is usually higher than memory suggests.
- Run the three-scenario formula, starting with the worst-case shortcut. Thirty minutes.
- Check your spouse's enrollment elections for a general-purpose FSA before either of you finalizes anything.
- If the HDHP wins, set the payroll HSA deduction to reach $8,750 (plus catch-up if applicable) through payroll rather than direct deposit, to capture the Medicare-tax exemption.
- Put a calendar reminder on next year's open enrollment to redo the arithmetic — the inputs change annually and so can the answer.
None of this requires a subscription or a spreadsheet template — the formula above works with or without us. What it requires is refusing to let a break-room anecdote make a four-figure decision for your household. This is education, not individualized financial advice.