Ask your team which insurance plan hurts most and you will get an instant answer. Ask what that plan costs per hour of chair time and the room goes quiet. That silence is expensive. Getting paid properly by the plans you already accept is one of the few levers that can move everything at once: more income from the same chairs, a schedule that does not have to be packed to break even, and treatment plans that stop being shadowed by write-offs. It starts with one number almost nobody has. To calculate your PPO write-offs, subtract the carrier's allowed fee from your full fee, total the gap across a month of the plan's patients, then divide by the chair hours those patients used. Three numbers from your practice software, one division, and a worked example below to copy.
The pain is universal: in the ADA Health Policy Institute's fourth-quarter 2025 survey of owner dentists, 55 percent named low insurance reimbursement a top challenge for 2026, ahead of staffing and rising overhead. The number behind the frustration usually goes unmeasured.
What is a PPO write-off?
A PPO write-off is the difference between your full fee and the amount your network contract allows, adjusted off the patient's ledger because your participation agreement requires it. Suppose your crown fee is $1,400 and the plan allows $980: the write-off is $420 on that single crown. (Round examples, not benchmarks. Honest write-off math starts from your own fees, never an industry average.)
Write-offs never arrive as a bill; they hide in an adjustments column most owners only see summed at year end. But a write-off is a price, the discount you sell the network in exchange for patient flow, and it deserves measuring in the unit you actually sell: chair time. A percentage says how hard the discount bites, not how much of your capacity the plan occupies. A high-volume network at a moderate discount can cost more per hour, and far more per month, than the small plan with the outrageous percentage everyone complains about.
The three numbers you need (and where to find them)
Your practice software produces all three for any date range, grouped by carrier or plan:
- Production at your full feesfor the plan's patients, usually labeled gross production. One month is enough.
- Insurance adjustments for the same patients over the same range: the write-off itself.
- Chair hours those patients used. Sum appointment lengths or estimate; consistency across plans matters more than precision.
Then divide: adjustments ÷ chair hours is the write-off cost per chair hour; the monthly figure times twelve is the annual picture. The first pass takes about twenty minutes; the calculator above does the arithmetic as you type.
Before you trust any report: submit your full fee on every claim and enter it on every ledger line, never the plan's allowed amount. Entering the contracted fee feels tidy, and it quietly destroys the data: the write-off report reads near zero while the real gap disappears from view. It costs you twice: carriers can use submitted charges when setting future maximum allowables, so a discounted fee today anchors your next schedule lower.
Which plan is really your worst? A worked example
Two plans, one month, round example numbers.
| One month | Plan A, the big network | Plan B, the ugly percentage |
|---|---|---|
| Production at your full fees | $30,000 | $10,000 |
| Write-off percentage | 25% | 40% |
| Dollars written off | $7,500 | $4,000 |
| Chair hours used | 60 | 40 |
| Write-off per chair hour | $125 | $100 |
| Collected per chair hour | $375 | $150 |
Ask the team and everyone points at Plan B: forty percent off the top is offensive. But run the division. Plan A writes off $125 for every hour its patients sit in your chairs, more than B's $100, and its monthly pool ($7,500) is nearly double B's ($4,000). The plans fail in different ways, and that is the point:
- Plan A is the negotiation priority.The biggest pool of adjusted-off dollars sits there, and its volume multiplies any win: a few points on A's allowed fees recovers more than a big concession from B.
- Plan B is the participation review.The deciding row is the last: $150 collected per chair hour against your cost of keeping a chair open (annual overhead before dentist pay divided by annual chair hours; $540,000 across 3,600 hours is $150, example numbers again). On those figures B fills your schedule at breakeven: those hours pay the practice's bills, not you.
Neither verdict is visible from the percentage alone. Everyone arguing about the worst PPO at lunch is ranking on the wrong number.
What your per-hour number is (and is not) telling you
Write-off per chair hour measures the gap between your fees and the contract's fees. It is not a pile of recoverable cash: no carrier is obligated to raise fees, and no negotiation converts the whole gap. It gives you a ranked decision list instead of a vague grievance: which schedule to challenge first, which plan sits below your cost of being open, and which is actually fine.
If the math points somewhere uncomfortable, you are in company: in the same survey, 29 percent of owner dentists dropped at least one network during 2025. Owners who do this well decide from plan-level numbers, in sequence: negotiate the biggest pools first, fix how claims route through leased networks second, and only then drop a single worst plan, with a landing plan for its patients.
What to do with your ranking, starting Monday
- Re-run the three numbers quarterly. Rankings shift with treatment mix, and wins erode when a schedule quietly changes underneath you.
- Build the dossier for your top target: highest-revenue procedures, their frequency, current allowed amounts, target fees. Do it alone; comparing fees with other practices is an antitrust problem, not a tactic.
- Ask in writing whether the carrier leases its network, and whether new fees follow the lease. A raise that does not follow the lease is half a raise.
- Verify the win on your next EOBs, then calendar an annual review. A negotiation is done when the EOBs match the letter; a missed review is a year at the old schedule.
Run the division this week. You should know what an hour of chair time pays you, plan by plan. (If pulling the reports sounds like a weekend you do not have, that untangling is the job Enamelogic was built to do.)
Questions dentists ask about write-offs
What is the average dental PPO write-off percentage?
The 30 to 45 percent figures quoted everywhere online have no published methodology behind them; no reliable public average exists. Your own average is knowable this afternoon: divide insurance adjustments by production at full fees over the last 90 days, plan by plan. That number is one you can act on.
Can I bill the patient for the written-off amount?
Not for covered services while in network: the adjustment is a contract obligation, and balance billing it violates the contract, sometimes the law. If a payment lands below your direct contract's schedule, ask the carrier in writing which network priced the claim; leased repricing is worth disputing on paper.
Does a big write-off number mean I should drop the plan?
Not by itself. A big write-off per hour with strong collections per hour usually marks a negotiation target, not a drop candidate. The drop conversation starts when collected dollars per chair hour sit at or below your hourly cost of being open and a prepared negotiation has failed. Even then, drop one plan at a time with a landing plan, and talk it through with your CPA before terminating any contract.