Timely Filing Limit

What timely filing limit means

Timely filing limit is a contractual and regulatory deadline set by each payer that defines how long you have to get an initial claim into their system. The clock usually starts on the date of service for outpatient services or the date of discharge for inpatient or residential stays. Some payers use other events instead, such as the date of the primary payer's explanation of benefits for secondary claims.

Every payer sets its own limit. Medicare typically allows 1 calendar year from the date of service. Commercial plans and Medicaid plans often use shorter windows, such as 90 or 180 days, and behavioral health carve-out vendors may use their own timelines inside the broader health plan.

Timely filing applies to the initial submission. Many payers require proof that an original claim was filed within the limit when you send corrected claims, reconsiderations, or appeals. If you cannot show that the original claim was received on time, you risk a permanent non-payable denial tied to timely filing.

Why timely filing matters operationally

Timely filing is one of the most expensive preventable problems in revenue cycle. Once a payer issues a true timely-filing denial, the claim is usually not appealable on medical necessity or coding grounds. The revenue is simply lost, and the payer will point to the contract language and benefit handbook.

Operationally, timely filing exposes gaps in:

• Charge capture and documentation lag (for example, residential days not being signed off for weeks).
• Front-end intake and benefits verification accuracy.
• Claim edits and workqueue management (claims stuck in "pending review" until after the clock runs out).
• Coordination-of-benefits handling when multiple coverages exist.

Because the limit is hard and external, you cannot fix timely-filing issues with cleaner posting or better follow up alone. You need controls that prevent claims from aging past payer limits. That means accurate payer selection, fast documentation, aggressive routing of clearinghouse rejections, and close tracking of claim age from service date, not from "when the team was ready to bill."

How to read and apply timely filing rules

Payer timely filing rules live in multiple places: provider manuals, contracts, fee schedules, and sometimes state regulations. When you read these rules, clarify three things:

• What event starts the clock (date of service, date of discharge, date of primary EOB, or date of eligibility determination).
• What counts as receipt (EDI acceptance by the payer, not just submission to the clearinghouse).
• Whether the rule differs for inpatient, outpatient, behavioral health, or specific products.

For secondary and tertiary claims, payers often start the clock from the date of the prior payer's EOB. In those cases, you must keep a copy of the primary EOB and the claim submission proof to respond when a secondary payer issues a CO-109 or similar denial and requests evidence that the primary claim was filed on time.

For corrections and appeals, most payers do not restart the timely filing clock. The key date is the original, on-time submission. You should retain:

• Clearinghouse acceptance reports.
• Payer 277CA acknowledgments.
• Any paper submission receipts, if you still send paper in rare cases.

If a payer issues a routing denial or an eligibility correction that causes you to bill a different entity, you need clear internal rules for how to measure the new timely filing window and how fast your team must re-submit so you do not age out with the correct payer.

• Treating the clearinghouse submission date as proof of timely filing, then discovering during an appeal that the file never reached the payer and you have no payer-level acceptance to show the claim was timely.
• Starting the clock from the date the clinician signed the note in your EHR instead of from the actual date of service, which hides true risk and allows PHP or IOP services to age past the payer's filing limit before anyone notices.
• Assuming a resubmission or corrected claim restarts the timely filing window, then sending a corrected UB-04 for a residential stay months later only to get a CO-29 timely filing denial because the original claim was never accepted.
• Ignoring different timelines for secondary claims, so your team waits to bill Medicaid secondary on an intensive outpatient episode until long after the primary EOB, and Medicaid denies for exceeding its secondary timely filing rule.
• Failing to document coordination-of-benefits changes, so when a behavioral health payer denies with CO-109 and you try to appeal on timely filing grounds, you cannot prove when eligibility changed or when the original claim left your system.

Timely filing is especially painful in behavioral health because claims often touch multiple entities before they land in the correct spot. Many health plans carve out behavioral health to a different vendor, and your intake staff may send the first claim to the medical payer that shows in the portal. By the time a routing denial comes back, the behavioral health carve-out may already be weeks into a 90-day filing limit.

Coordination-of-benefits errors drive the same risk. Clients may present with multiple coverages: commercial primary with Medicaid secondary, EAP sessions that convert to health-plan billing, or Medicare with a behavioral health carve-out. If the first claim goes to the wrong primary, or COB is set up incorrectly, timely filing can expire while your team moves the claim across payers.

For long episodes like residential, PHP, or IOP, documentation lag makes this worse. If your clinicians finalize encounters or group notes weeks after services, the billing office may not even see the charges until late in the timely filing window. A string of per-diem days that is billed late can erase tens of thousands of dollars if a payer applies a strict filing rule.

Operationally, behavioral health programs should treat routing denials as same-day emergencies. When a claim comes back with a payer-routing or COB-related denial, re-verify eligibility, confirm the correct behavioral health vendor, and resubmit the claim that same day. That habit alone can save significant revenue that would otherwise die to timely filing on the correct payer.

AI can monitor timely filing risk by watching claim age in real time and cross-checking it against payer-specific filing windows. An agent can read payer contracts and provider manuals once, store the filing limits by product, and then flag any open encounters or unsent claims that are approaching each payer's deadline. AI can also watch clearinghouse and payer acknowledgment files, identify routing or eligibility denials, and immediately queue those claims for same-day correction before the clock runs out.

Supabill's claims-scrubbing and denials agents can hold payer-specific timely filing rules in context, watch every 277/835, and tag CO-22 and CO-109 denials that relate to routing or filing issues so the team can react before the remaining window closes. A benefits-verification agent can help reduce the problem at the front end by validating the correct behavioral health payer and carve-out vendor during intake. The limit: AI cannot negotiate exceptions or argue unusual hardship cases with payers, so humans still need to handle complex appeals, contract interpretation disputes, and any outreach where you are asking a payer to make a one-time exception on a missed deadline.

How is timely filing limit different from the deadline to appeal a denial?

Timely filing limit controls how long you have to submit an initial claim to a payer. Appeal deadlines control how long you have to dispute a denial on a claim that was already submitted on time. You might have 90 or 180 days for timely filing but only 30 or 60 days to appeal a denial on that same claim. Once timely filing has passed, you cannot fix the problem with an appeal unless the payer's policy explicitly allows an exception or special review. Source

What is Medicare's timely filing limit for behavioral health claims?

For most Medicare claims, including behavioral health services, the timely filing limit is 1 calendar year from the date of service. That means a claim for a service on March 10, 2025 must be received by Medicare no later than March 10, 2026. The same 1-year rule applies whether the service is billed on a CMS-1500 or a UB-04, and Medicare requires documentation proving timely submission if you are asking for an exception or reprocessing. Source

Does resubmitting or correcting a claim restart the timely filing clock?

No. In most payer policies, the timely filing window is based on the original date of service and the date the payer first received a claim for those services. Corrected claims, reconsiderations, and appeals do not restart the clock. When you resubmit, you must be able to show that an original claim was filed within the payer's limit, using acceptance reports, clearinghouse records, or other proof of timely submission. Source

How can I appeal a timely filing denial caused by coordination-of-benefits confusion?

If a claim went to the wrong payer first because eligibility or COB information was incorrect, some payers will consider an appeal if you can prove that: the member's coverage information changed, you submitted to the original payer within its filing limit, and you redirected the claim promptly once you received the routing denial or updated EOB. Include eligibility screenshots, the original EDI acceptance, and the denial from the first payer when you appeal to the correct payer, and explicitly connect the dates to the payer's written policy. Source

What is the best way for a behavioral health program with long stays to manage timely filing risk?

For residential, PHP, and IOP programs, build workflows that generate interim bills or weekly claims so you are not sitting on months of per-diem days that have not been billed. Require clinicians to complete notes within a fixed short window, then feed those charges straight into a workqueue that sorts by payer and days since service. Finally, monitor routing and eligibility denials daily, and require same-day re-verification and rerouting whenever a payer sends a CO-22 or similar denial so that you stay inside the correct payer's timely filing window. Source

• CMS — Medicare claims processing