A timely filing limit is the deadline for getting a claim to the payer, counted from the date of service. Miss it and the claim denies with CO-29, usually for good. Medicare allows 12 months. Most commercial contracts allow far less, and that gap is where practices lose money.
1. What a timely filing limit is
Every payer sets a window for submitting claims. Claims that arrive late deny with CARC 29: the time limit for filing has expired. Because the group code is usually CO, the provider writes off the amount and cannot bill the patient. There are often separate, shorter deadlines for corrected claims and appeals.
2. Timely filing limits by payer
| Payer | Initial claim deadline | Where to confirm |
|---|---|---|
| Original Medicare | 12 months (one calendar year) from the date of service | 42 CFR 424.44; your MAC's website |
| Medicare Advantage | Set by the plan contract; often shorter than 12 months for contracted providers | The plan's provider manual and your contract |
| Medicaid (fee-for-service) | Federal rules require submission within 12 months of the date of service; states can set shorter limits | 42 CFR 447.45; your state Medicaid provider manual |
| Medicaid managed care | Set by the state and the plan; commonly well under 12 months | The plan's provider manual |
| TRICARE | 1 year from the date of service | TRICARE regional contractor provider manual |
| VA Community Care | 180 days from the date of service | VA community care provider resources |
| Commercial plans (UnitedHealthcare, Aetna, Cigna, BCBS plans, Humana, others) | Set by your contract; 90 to 180 days is common for participating providers | Your contract and the payer's provider manual |
Why we do not list one number per commercial payerCommercial limits differ by contract, product line (commercial, Medicare Advantage, Medicaid plans), state, and participation status, and payers revise them. A number from a website is not a defense in an appeal. Your contract is. Keep a payer-by-payer table built from your own contracts and provider manuals.
3. How the clock really works
- The clock usually starts on the date of service (or the discharge date for inpatient claims). Check each contract for its exact rule.
- Rejected claims generally do not stop the clock. A claim rejected at the clearinghouse or returned as unprocessable (for example CO-16 with MA130) is usually treated as never filed. See our CO-16 guide.
- Secondary claims often run from the primary payer's remittance date, not the date of service. Check the secondary payer's rule.
- Corrected claims and appeals have their own deadlines. Medicare redetermination requests are due within 120 days of receiving the initial determination.
- Medicare has narrow exceptions, such as administrative error by Medicare or its contractor, and retroactive Medicare entitlement.
4. Proof of timely filing
If a payer denies for timely filing and you did file on time, you need evidence. The strongest proof is:
- Clearinghouse acceptance reports showing the payer accepted the claim on a specific date (for example the 277CA claim acknowledgment).
- Payer acknowledgment or claim status responses showing receipt.
- Prior denial or correspondence from the payer that proves the claim was in their system before the deadline.
A screenshot of your billing system showing "sent" is weak evidence. Save the acceptance reports where you can find them by claim.
5. Appealing a CO-29 denial
- Appeal if you have proof of on-time submission, or if the delay qualifies for a documented exception (for example retroactive eligibility).
- Do not appeal without proof. Payers rarely overturn CO-29 on a request alone, and the time is better spent on recoverable denials.
- Find the root cause: charge lag, claims stuck in a hold queue, rejections nobody worked, or a secondary claim that was never sent.
The recovery workflow is in our denial recovery playbook.
6. How to never miss a deadline
- Calculate a deadline for every claim at creation, based on payer and contract, and show days remaining on every work queue.
- Work rejections daily. Rejections that sit unworked are the most common path to CO-29.
- Measure charge lag, the days from service to charge entry. A practice with 10 days of charge lag and a 90-day limit has lost more than a tenth of its window before billing starts. See missed charge capture.
- Sort aged AR by deadline, not just by age. A 70-day claim with a 90-day limit is more urgent than a 120-day Medicare claim. Our days in AR guide covers aging.
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See the AI Biller →Frequently asked questions
What is the timely filing limit for Medicare?
Original Medicare requires claims to be filed within 12 months (one calendar year) of the date of service, under 42 CFR 424.44. Medicare Advantage plans set their own limits by contract.
What is the timely filing limit for Medicaid?
Federal rules require Medicaid claims within 12 months of the date of service, but states can set shorter limits, and Medicaid managed care plans often do. Check your state and plan provider manuals.
What is the timely filing limit for commercial insurance?
It is set by your contract. 90 to 180 days from the date of service is common for participating providers, and limits vary by product line and state. Check your contract and the payer's provider manual.
What denial code is used for timely filing?
CARC 29: the time limit for filing has expired. It usually comes with the CO group code, so the provider cannot bill the patient.
Does a rejected claim count as filed for timely filing?
Generally no. Claims rejected at the clearinghouse or returned as unprocessable are usually treated as never filed, so the original deadline still applies.
What counts as proof of timely filing?
Clearinghouse acceptance reports showing the payer accepted the claim, payer acknowledgments or claim status responses, and earlier payer correspondence about the claim.
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