Underpayment Calculator

Compare the contractually expected payment against what the payer actually paid — per claim, and scaled to monthly and annual exposure.

The leak nobody notices

Denials announce themselves; underpayments don’t. A claim paid at $500 against a $650 contractual expectation looks “paid” in every aging report — the $150 simply never arrives, claim after claim. Enter the expected and actual payments, and optionally how many similar claims a month you run, and this calculator returns the per-claim variance and what it compounds to.

How to use it

  1. Enter the expected payment from the payer contract or fee schedule.
  2. Enter the actual payment from the remittance.
  3. Add monthly claim volume to see the exposure at scale.

The formulas

underpayment = expected − actual · variance% = underpayment ÷ expected

A worked example

Expected $650, paid $500: a $150 underpayment — a 23.1% variance, far beyond rounding. At 40 similar claims a month that is $6,000 monthly and $72,000 a year from one payer-code combination alone, which is why underpayment detection consistently ranks among the highest-ROI activities in revenue cycle work: the money was already earned, contracted and billed.

Estimates only — payer contracts, plan documents and the EOB are always the source of truth, and nothing here is billing, legal or medical advice. The calculator runs entirely in your browser: no patient data is entered, transmitted or stored.

Common questions

Where does the “expected” figure come from?
The payer contract’s fee schedule — loaded into the PM system so every remit can auto-compare. Without loaded contracts, underpayments are essentially invisible.
How much variance is worth chasing?
Set a materiality floor (say $10–25 per claim) and chase patterns, not pennies — one systematic $150 short-pay across a code family beats a hundred random $3 variances.
Are underpayments appealable like denials?
Yes — with the contract language as the exhibit. Payers correct systematic short-pays when confronted with the math; the calculator’s annualised figure is exactly that math.