Medicare Timely Filing Limit: The 12-Month Rule, Its Exceptions and a Checklist
The Medicare timely filing limit is one calendar year from the date of service: its four exceptions, what happens after it, and how commercial plans differ.
The short answer
- 01Medicare must receive a claim within one calendar year after the date of service, judged by the date the contractor receives it
- 02Only four exceptions extend the limit, and each comes from an error or a retroactive coverage change outside your control
- 03A claim denied as late cannot be appealed, and you generally cannot bill the patient for it, so the fix is a process that never lets a claim age
In October, the billing lead at Main Street Clinic finds a stack of claims from the previous autumn that never went out. A provider left without signing several notes, the encounters waited, and nobody owned them. Some of the dates of service are 11 months old. A few are 13. The 11-month claims can still be sent this week. The 13-month claims are almost certainly lost, because the Medicare timely filing limit is one calendar year from the date of service, and for most late claims there is no appeal.
Below: the rule, the four exceptions, what happens after the deadline, and a checklist so you never find a stack like that.
What is the Medicare timely filing limit?
A Medicare claim must be filed no later than the close of the period ending one calendar year after the date of service. That is the rule in 42 CFR 424.44(a)(1), and it applies to services on or after January 1, 2010, when the Affordable Care Act shortened the old, longer windows.
Three details in the Medicare Claims Processing Manual, chapter 1, section 70, decide whether a claim makes it:
- Which date starts the clock. Generally the date of service, the "From" date on the claim. For a professional claim with a span of dates, each line's "From" date counts; if a line's first date is late, that part of the line is denied. For an institutional claim with a span, the "Through" date is used.
- Which date stops it. The date the Medicare Administrative Contractor (MAC) receives the claim, not the date you sent it.
- What counts as received. Only a claim that passes the basic edits. A rejected claim was never filed, so its clock keeps running until a corrected claim gets through.
A small trap: a claim for a service on February 29 must be filed by February 28 of the following year.
What are the exceptions to the timely filing limit?
There are four, listed in 42 CFR 424.44(b) and explained in section 70.7 of the manual. Each one comes from something outside the practice's control.
| Exception | What happened | Key condition |
|---|---|---|
| Administrative error | A Medicare employee, contractor or agent made an error or misrepresentation that caused the late filing | Requests are not accepted beyond 4 years from the date of service |
| Retroactive Medicare entitlement | The patient was not entitled to Medicare on the date of service, then received entitlement back to that date | You document when entitlement was granted |
| Retroactive entitlement with State Medicaid | As above, and the State Medicaid agency took back its payment 6 months or more after the service | The recoupment came 6 or more months after the service |
| Retroactive disenrollment from Medicare Advantage or PACE | The patient was in a Medicare Advantage plan or PACE, was disenrolled back to the date of service, and the plan took back its payment | The recoupment came 6 or more months after the service |
When an exception applies, the deadline is generally extended through the last day of the sixth calendar month after the month in which the error was corrected or the retroactive change was notified. You request the exception from your MAC with the documents that prove the conditions were met.
Notice what is not on the list: staff turnover, a provider who did not sign notes, a software change, a lost claim or a busy month. None of those extends the limit.
What happens after the deadline passes?
Three things, all bad for the practice.
- The claim is denied as untimely. Medicare denies a claim received more than 12 months after the date of service.
- You cannot appeal it. Per section 70.4 of the manual, a timely filing denial is not an "initial determination", so it is not subject to appeal. The only way back in is an exception.
- You generally cannot bill the patient. When the provider is responsible for the late claim, it may not charge the patient for the service beyond the deductible and coinsurance that would have applied if Medicare had paid.
If you file a late claim with no explanation, the contractor assumes the provider accepts responsibility. If you believe the patient caused the delay, the manual describes filing a no-payment claim with an explanation of why.
There is one more limit to know. Once the filing period has passed, you cannot add a service you left off the original claim. Correcting information on a claim that was filed on time is a different matter, handled as a reopening under its own time limits.
How do commercial timely filing limits compare?
Commercial plans set their own limits, and they are often shorter than Medicare's. There is no single number to remember. The limit for each plan is in your contract and the plan's provider manual, and it can differ by product line. Some points to check for each plan:
- the number of days for a first claim;
- the number of days for a corrected claim, which may be different;
- whether a secondary claim's clock starts from the date of service or from the primary payer's decision;
- what proof the plan accepts that a claim was sent on time.
Medicare Advantage plans are part of Medicare, but if you are contracted with one, your contract sets the filing limit. State law may also set rules for plans regulated in your state, so ask your state medical society or counsel if a limit looks unfair.
Medicare timely filing checklist
Use this to make sure a claim never reaches its deadline unnoticed.
- Sign notes within days, not weeks. An unsigned encounter is a claim that cannot be built. Track unsigned notes by provider.
- Set an internal deadline far inside the limit. Treat 60 or 90 days as your own limit, so the 12 months is a backstop, not a target.
- Work rejections the day they come back. A rejected claim has not been filed. Our article on claim rejection vs denial explains why the difference matters.
- Keep acceptance reports. The acknowledgment that a payer received your claim is your proof of timely filing. Store it with the claim.
- Age your open claims every week. List every claim, or encounter not yet billed, by date of service, oldest first.
- Verify coverage before the visit. Billing the wrong payer first can burn months. Re-check monthly for recurring services.
- Watch for retroactive changes. When Medicaid or a Medicare Advantage plan takes back a payment, check at once whether a Medicare exception applies, and note the notification date.
- Keep a table of commercial limits. One row per plan, with the first-claim, corrected-claim and secondary-claim limits.
- Read the denial code. A timely filing denial is usually CO-29. Our guide to common claim denial reasons covers it and the others.
Frequently asked questions
What is the Medicare timely filing limit?
Medicare must receive a claim no later than one calendar year after the date of service. The deadline is judged by the date the Medicare contractor receives the claim, not the date it was sent.
Can a Medicare timely filing denial be appealed?
No. A claim denied for late filing is not an initial determination, so it cannot be appealed. A late claim can only be paid if one of the four regulatory exceptions applies.
What are the exceptions to Medicare's timely filing limit?
Administrative error by Medicare or its contractors, retroactive Medicare entitlement, retroactive entitlement where a State Medicaid agency recouped its payment 6 or more months after the service, and retroactive disenrollment from a Medicare Advantage plan or PACE where the plan recouped its payment 6 or more months after the service.
Can I bill the patient if I missed Medicare's filing deadline?
Generally no. When the provider is responsible for the late filing, it may not charge the patient beyond the deductible and coinsurance that would have applied if Medicare had paid.
Do commercial insurance plans use the same 12-month limit?
No. Each commercial plan sets its own limit in its contract and provider manual, and many are shorter than Medicare's. Check each plan's limits for first claims, corrected claims and secondary claims.