Medicare Secondary Payer Payment Calculator
The MSP payment calculator is intended to provide an approximation of what an MSP payment may be for assigned claims. This calculator does not reflect applicable coinsurance, deductible, or other deductions. MSP claims are calculated linebyline. Any billing and/or refunds should be done based on your remittance advice and not the results of this calculator.
Here’s what you'll need to get started:
 Your Billed Amount
 Medicare Fee Schedule Allowed Amount
 Primary Insurance Allowed Amount
 Primary Insurance Paid Amount
 Obligated To Accept payment in Full (OTAF), if applicable
Note: The OTAF amount will indicate that there is a discount that the beneficiary is not responsible for. To calculate the OTAF, use the primary explanation of benefits, take the billed amount and minus any discounts or adjustments.
Enter the information in the Enter Payment Data fields and select Calculate.
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How to Determine the Medicare Secondary Payment Amounts
First, the MSP payment is determined by the following:
 Actual charge by physician/supplier or OTAF minus amount paid by primary
 Usual Medicare payment determination
 Fee Schedule amount (minus any unmet deductible 2024 ‒ $240)
 Multiply results by 80% (or other as appropriate)
 Highest allowed amount minus amount paid by primary
 MPFS or amount payable under Medicare (not including deductible or coinsurance)
 Primary payer’s allowed amount
Last, the Medicare payment is the littlest of the three amounts.
Example  Calculation 



Related Content
 Medicare Secondary Payer
 MSP PostPay Overpayment Forms
 Coordination of Benefits & Recovery Overview
 CMS IOM Publication 10005, Medicare Secondary Payer Manual, Chapter 3
Revised 7/29/2024