Timely Filing Limits by Payer and How Practices Protect Every Claim

A timely filing limit is the deadline by which a payer must receive a claim, counted in most cases from the date of service. Original Medicare allows 12 months under 42 CFR 424.44, commercial plans commonly allow between 90 and 180 days and state Medicaid programs set their own windows that range from roughly three months to a full year. A claim that misses the applicable deadline is denied with reason code CO-29. That revenue is almost always lost permanently.

The risk appears when a claim is rejected, held for missing information or routed to the wrong payer, because the filing clock keeps running throughout each delay. For practice owners and billing managers, protecting revenue in 2026 depends on knowing each payer’s window and on building a process that tracks the time remaining on every open claim.

Timely Filing Limits Vary Widely Across Payer Types

No single national standard applies to every claim. Medicare’s limit is set by federal regulation, Medicaid limits are defined in each state’s provider manual and commercial limits are written into the participation agreement a practice signs with each plan.

Payer Type	Typical Filing Limit	When the Clock Starts	Governing Source
Original Medicare, professional claims	12 months	The “From” date of service	42 CFR 424.44
Original Medicare, institutional claims	12 months	The “Through” date on the claim	42 CFR 424.44
Medicare Advantage	Set by plan, often 90 to 365 days	Date of service	Plan contract
State Medicaid	Roughly 90 days to 12 months	Date of service	State Medicaid provider manual
Commercial plans	Commonly 90 to 180 days	Date of service	Participation agreement
Secondary claims	Varies by payer	Often the primary payer’s remittance date	Payer policy

State examples illustrate how much these windows differ. Texas Medicaid allows 95 days from the date of service, while California’s Medi-Cal program allows six months. A practice should also confirm the filing clause in each executed contract rather than relying on a general payer reference list.

Medicare Applies a Strict One-Year Rule With Narrow Exceptions

Section 6404 of the Affordable Care Act reduced the Medicare filing window to one calendar year from the date of service. CMS implements that rule through 42 CFR 424.44 and Chapter 1, Section 70 of the Medicare Claims Processing Manual. As of the eCFR text current through 2026, the regulation permits an extension only in limited circumstances. These include an error or misrepresentation by a Medicare contractor or CMS employee, retroactive Medicare entitlement, retroactive Medicare entitlement in which a state Medicaid agency recovers its earlier payment and retroactive disenrollment from a Medicare Advantage plan.

Each exception requires documentation. A Medicare Administrative Contractor will not extend the deadline simply because a claim was delayed internally. When a Medicare claim is denied for untimely filing, the balance generally cannot be transferred to the patient, which makes the loss a direct reduction in practice revenue.

Rejected Claims Do Not Stop the Filing Clock

Many practices assume that sending a claim before the deadline satisfies the requirement. Payers, however, measure timeliness by when they receive a claim they can process. A claim rejected as unprocessable at the clearinghouse or the payer front end is not considered filed, so the deadline continues to run until a corrected version is accepted.

This distinction matters when a payer later denies a claim for timely filing that the practice believes it submitted on time. In that situation, the appeal depends on dated evidence that the payer received and accepted the original submission. Acceptable proof typically includes the following:

• A clearinghouse acceptance report showing the payer received the claim
• An electronic claim acknowledgment confirming acceptance into the payer’s system
• A payer portal record displaying the original receipt date
• A remittance advice or letter that references the earlier claim

Corrected Claims and Appeals Follow Separate Deadlines

A payment determination does not end the timing obligations attached to a claim. Corrections and disputes each operate under their own windows, which often begin on a different date than the original filing limit.

Corrected and Replacement Claims

Many commercial payers require a corrected or replacement claim to be submitted within a defined period measured from the original remittance date. Medicare handles many minor clerical errors through a reopening process, which generally must be requested within one year of the initial determination.

Appeals After a Payer Determination

Appeals carry a separate set of deadlines. A Medicare redetermination must be requested within 120 days of receiving the initial determination, while commercial appeal windows are defined in each plan’s provider manual and frequently include a second appeal level with its own limit.

Credentialing and Eligibility Gaps Consume Filing Windows

Some of the most expensive timely filing losses begin before a claim is created. A provider who sees patients while enrollment is still pending may need to hold claims until the payer approves participation. Medicare permits limited retrospective billing for newly enrolled physicians, generally up to 30 days before the effective date, but commercial payers are often less flexible. Reliable medical credentialing services shorten that waiting period and reduce the number of claims held against a running deadline.

Coverage errors create a similar problem. When a claim is first sent to the wrong payer, the time spent waiting for that denial counts against the correct payer’s window. Accurate insurance eligibility verification before each visit confirms the active plan and payer order at the outset. Patients with more than one plan add another layer, since secondary payers often measure their deadline from the primary payer’s remittance, a sequence explained in our overview of coordination of benefits rules.

A Filing Calendar Turns Deadlines Into Daily Workload

Practices that rarely lose claims to timely filing treat each deadline as a scheduled task rather than as a reminder that appears only when a claim is nearly expired. A dependable process includes the following controls:

• A payer reference table listing initial, corrected claim and appeal deadlines for each contract
• Internal submission targets set well ahead of every payer limit
• Daily review of clearinghouse rejections so corrections are sent within one business day
• Aging reports sorted by days remaining in the filing window rather than by days since service
• Saved acceptance reports for every batch to support future appeals

The most effective protection remains a claim that is accepted on the first submission, which is why practices focused on submitting clean claims rarely face filing deadline disputes. When claims do stall, the underlying causes usually match the reasons for delayed payments found elsewhere in the revenue cycle.

Older balances require structured follow-up before their windows close. Professional accounts receivable management prioritizes open claims by remaining filing time and dollar value so that recoverable revenue is pursued while it can still be paid.

Final Thoughts

Timely filing limits are among the few billing rules that allow no recovery once a deadline passes, which makes prevention the only reliable strategy. Medlife MBS helps practices maintain payer-specific filing calendars, resolve rejections before deadlines approach and preserve proof of submission for every claim. With each deadline tracked from the date of service through final payment, Medlife MBS keeps earned revenue from expiring in the claim queue.