Timely Filing Limits by Payer: A Reference Guide for Practices, and Why Your Real Deadline Is Shorter

Your biller pulls up a remittance and there it is: CO-29. The visit was documented, the codes were right, the patient was eligible, and the payer will not pay a cent. The claim didn’t fail on merit. It failed on the calendar. And because your participation agreement almost certainly bars you from billing the patient for it, the full charge lands on your write-off report.

This guide gives you a working reference for timely filing limits by payer, including Medicare, Medicaid, and the major commercial plans, along with the corrected claim filing window and appeal deadlines that sit behind them. More importantly, it shows you why the payer’s published deadline is not the deadline your practice should be working to, and how to set an internal submit-by date that keeps every claim far from the edge.

We work inside the billing workflows of independent practices every day at Care VMA. The pattern is remarkably consistent: timely filing losses are almost never caused by someone forgetting a payer’s rule. They happen because days quietly disappear inside the practice before the claim ever leaves.

A Clean Claim Can Still Be a Total Loss

Picture a pattern we see repeatedly in multi-payer primary care practices. A claim goes out on day 12 after the visit. That’s reasonable. The clearinghouse rejects it on day 13 because the subscriber ID on file belongs to last year’s plan. The rejection lands in a report nobody opens that week, or the next. On day 97, during a routine aging review, someone notices the claim never reached the payer. The payer’s in-network limit was 90 days.

Nothing about that claim was wrong clinically. The coding was clean. The fix took four minutes once someone saw it.

That’s what makes timely filing different from every other denial category. A coding denial can be corrected. A medical necessity denial can be argued. A late claim is simply over, and for Medicare fee-for-service claims, a claim denied due to timely filing does not have appeal rights.

In our experience, practices that suffer repeated CO-29 write-offs don’t have a knowledge problem. They have a visibility problem. The rest of this guide is about fixing that.

Timely Filing Limits by Payer: 2026 Reference Table

A timely filing limit is the maximum time a payer allows between the date of service and the payer’s receipt of a valid claim. Miss it and the claim denies with claim adjustment reason code 29, which means the time limit for filing the claim has expired.

The Three Deadlines Every Claim Carries

Every claim you bill actually lives under three separate deadlines, and they rarely start on the same day:

1. Initial filing limit: the window to get the original claim received by the payer, usually counted from the date of service.
2. Corrected claim filing window: the window to replace or adjust a claim the payer already processed. Some payers count it from the date of service, others from the original remittance.
3. Appeal or reconsideration window: the window to dispute a payer decision, usually counted from the remittance or denial notice.

A practice can be comfortably inside one clock and already out of time on another. That is exactly how appeals get lost on claims that were filed on time.

How to Read the Table

The table below summarizes published rules from each payer’s own policy documents and federal regulations. Treat it as a starting point for your own matrix, not a substitute for your contracts. Commercial numbers in particular can be shortened or lengthened by your participation agreement and by state law.

Figures reflect published policies reviewed in 2026. Medicare allows one calendar year from the date of service, Medicaid programs run from 90 days to 12 months depending on the state, and commercial plans commonly land between 90 and 365 days, with BCBS setting its limits plan by plan. Several of the largest commercial payers publish no national figure at all, because the number lives in your participation agreement.

Why the Numbers Online Disagree, and What Actually Starts and Stops the Clock

If you search for a single payer’s deadline, you will likely find three different answers on the first page. We checked. One reference lists Aetna at 120 days, another at 90, another at 180. Corrected claim windows for UnitedHealthcare appear as 180 days in one guide and 365 in another.

Most physicians don’t realize how common this is, or how risky it becomes when a biller copies a number from a blog into the practice management system and treats it as policy.

Your Participation Agreement Outranks Every Published Table

Commercial timely filing limits are contractual. Two practices in the same city can have different deadlines with the same payer because they signed different agreements, at different times, under different state rules. The practical rule we give every practice we work with is simple: the number in your contract wins, and if your contract is silent, the payer’s current provider manual wins. A blog table, including this one, is a checklist of what to look up.

That also means your matrix has an expiration date. Contracts renew, payers republish administrative guides every year, and Medicaid managed care plans change hands. A deadline matrix that nobody has touched since it was built is a liability.

What Starts the Clock, What Stops It, and What Doesn’t

The clock usually starts on the date of service. There are important variations. For Medicare institutional claims with a span of dates, the “Through” date on the claim is used for determining timeliness, while physician and supplier claims with date spans use the “From” date. Even calendar quirks matter: claims with a February 29 date of service must be filed by February 28 of the following year.

The clock stops only when the payer receives a valid claim. That single word, valid, is where most practices get hurt. A claim stopped by your clearinghouse or by the payer’s front-end edits was never accepted for adjudication, so nothing has been filed. Sending is not filing. Only acceptance counts.

Secondary claims run on a different clock. When a patient has multiple insurance plans, the secondary payer’s clock usually starts from the date the primary payer’s EOB was issued, not from the date of service. If your team waits for the secondary to “come due” based on the visit date, they are tracking the wrong clock.

Most Timely Filing Losses Begin in the First Two Weeks

When a practice comes to us after a string of CO-29 denials, the instinct is to look at the back end: the aging report, the follow-up queue, the biller who left. Those matter. But when we trace expired claims backward, the delay almost always started in the first 10 to 14 days after the visit.

Here is where the days go:

Unsigned documentation. A provider closes notes in batches on Friday, or at the end of the month. Every day a note sits unsigned is a day the claim cannot be built.

Charge entry lag. Charges wait for a coder, a superbill, or a batch run. In smaller practices, charge entry often happens “when there’s time,” which during flu season means rarely.

Holds nobody owns. Claims parked for a missing referral number, an authorization, or a newly hired provider whose credentialing isn’t finished. Credentialing holds are especially dangerous because the provider may not be loaded with the payer for weeks, and the clock keeps running the entire time.

Unread rejections. This is the single biggest source of expired claims we see. Clearinghouse rejection reports and payer acknowledgment files arrive daily. If no one is assigned to read them daily, a rejected claim looks exactly like a submitted claim in most workflows.

Eligibility surprises. A patient changed plans and the front desk didn’t catch it. The claim goes to the old payer, denies weeks later, and the correct payer’s window has been shrinking the whole time.

None of these is dramatic. Each one burns a few days. Stack three of them on a 90-day payer and your comfortable window is gone before anyone notices a problem.

In our view, this is why “work your aging report” is incomplete advice. A standard aging report tells you how old a claim is. It doesn’t tell you how much time the claim has left, and those are very different numbers when your payers range from 90 days to a full year.

The Filing Window Budget: Setting an Internal Submit-By Date for Every Payer

The framework we use with practices is built on one idea: treat each payer’s filing limit as a budget of days, and decide in advance how many days each internal step is allowed to spend. The payer’s deadline becomes the outer wall. Your internal submit-by date becomes the real deadline.

The math looks like this:

Effective window = Payer limit – documentation lag – charge entry and coding lag – scrub and transmission time – reserve for at least one rejection cycle

If your effective window on a 90-day payer is 30 days because of slow notes and unread rejection reports, you don’t have a 90-day payer. You have a 30-day payer.

Step 1: Build a Contract-First Deadline Matrix

List every payer and plan type you bill, then record four fields for each: initial filing limit, corrected claim window and its start point, appeal window and its start point, and secondary claim window. Source every cell from your participation agreement or the payer’s current manual, and write the source and date next to it. Where two sources disagree, use the shorter number until you confirm otherwise with the payer rep.

Step 2: Measure Your Own Lag Honestly

Pull 30 days of claims and measure, per provider, the median days from date of service to note signature and from signature to claim creation. Most practices are surprised by the spread between providers. This is also where you’ll find the provider whose notes consistently close two weeks late, which is a conversation worth having early.

Step 3: Set Payer-Tiered Submit-By Dates

Group payers into tiers by filing window, then set an internal submit-by target for each tier. Short-window payers (90 days or less) get the tightest target. Medicare and one-year payers can tolerate more room, though we still recommend treating every payer as if it had a short window, since it simplifies training and protects you when a contract quietly changes.

Worked Example: A 90-Day Commercial Payer

For a payer with a 90-day in-network limit, a budget we often recommend looks like this:

• Days 0-3: note signed and charges entered
• Days 4-7: claim scrubbed and transmitted
• Days 8-10: payer acceptance confirmed on the acknowledgment report
• Days 11-20: reserve for correcting and resubmitting any rejection
• Day 45: internal hard stop, any claim not yet accepted by the payer is escalated to the practice manager
• Days 46-90: protected buffer for eligibility corrections, COB delays, and payer errors

The buffer is not wasted time. It’s the space that turns a payer mistake into an inconvenience instead of a write-off.

Step 4: Reconcile Acceptance Daily, Not Submission

The only proof that stops the clock is payer acceptance. Dated 999 and 277CA acceptance reports carrying the batch ID and claim number are the strongest evidence, because they show the payer accepting the claim, while a transaction history from billing software alone is weaker since it shows sending rather than receipt. Someone must compare yesterday’s submissions against today’s acceptance and rejection files every business day. If your team is unclear on how those reports flow back, our guide to clearinghouse and billing software management walks through the handoff points where claims most often go missing.

Step 5: Work a Days-Remaining List, Not Just an Aging Report

Add a view that sorts open claims by days left before each payer’s limit, not by days elapsed. Impact Advisors describes a version of this as a “reverse aging” report that compares open claims to the timely filing limit table to identify claims with upcoming deadlines. A 70-day-old Medicare claim and a 70-day-old claim with a 90-day payer look identical on a standard aging report. On a days-remaining list, one of them is an emergency.

Corrected Claim Filing Windows, Appeals, and Other Places Practices Lose Claims They Already Filed

Filing on time is necessary. It isn’t sufficient. Some of the most frustrating losses we see involve claims that made the original deadline and still died later.

Treating a Correction Like an Appeal, or the Reverse

A corrected claim fixes your data: a wrong modifier, a missing diagnosis pointer, an incorrect date. An appeal disputes the payer’s decision. Sending one through the other’s channel wastes weeks and can burn both windows. Train your team to classify every denial before touching it: is this our error to correct, or their decision to dispute?

Assuming the Corrected Claim Window Matches the Original

Corrected claim windows don’t always behave like the original filing limit. Some payers measure from the date of service, some from the original remittance, and some simply apply the same deadline as the original claim. For Medicare, when the need for a correction is discovered beyond the claims timely filing limit, an adjustment bill is not allowed and a provider must use the reopening process. Record the corrected claim window and its start point as its own column in your matrix.

Appealing a CO-29 Without Proof

A timely filing appeal without dated evidence of payer receipt rarely succeeds. Before anyone drafts a letter, pull the acceptance report showing the payer received the claim within the window. If that report doesn’t exist, the appeal has nothing to stand on, and your time is better spent on the process fix.

Writing Off Before Checking the Exceptions

Some late claims are legitimately recoverable. Medicare regulations recognize four exceptions: error or misrepresentation by an employee, Medicare contractor, or HHS agent; retroactive Medicare entitlement; retroactive entitlement where a State Medicaid Agency recoups money 6 months or more after service; and recoupment by a Medicare Advantage plan or PACE organization after a retroactive disenrollment. When a Medicare program error caused the miss, the time limit is extended through the last day of the sixth calendar month following the month in which the error is rectified. Commercial payers often have their own exceptions, particularly for coordination of benefits delays when you can show the primary EOB date.

Letting Denied Claims Sit Unworked

The quietest loss of all: a claim is denied for a fixable reason, gets set aside, and the correction window expires while it waits. We’ve written about how often denied claims are never resubmitted at all, and timely filing is usually what finally closes the door on them.

Deadline Control for Practices With a Heavy Short-Window Payer Mix

Two practices can run identical workflows and carry very different risk. A practice billing mostly Medicare has a year of room on most claims. A practice where half the volume goes to commercial plans with 90-day windows and a state Medicaid program with a 95-day window has almost no slack at all. Payer mix should shape how tightly you staff and monitor the claim queue.

For practices ready to tighten this further, three moves make the biggest difference.

Assign single ownership of the acknowledgment files. Not “the billing team.” One named person, with a backup, who reads rejection and acceptance reports every business day and closes each item. Shared ownership is how rejection reports go unread for two weeks.

Tie matrix updates to contract events. Every renewal, amendment, new payer, or new Medicaid managed care plan triggers a matrix review. So does the annual release of each major payer’s administrative guide.

Report untimely write-offs as their own KPI. Track CO-29 dollars and claim counts monthly, separately from other denials, next to days in AR. If you’re building a broader measurement set, our breakdown of billing analytics and RCM KPIs covers how to structure that review so it drives action rather than just reporting.

This is also where many independent practices hit a staffing wall. Daily acceptance reconciliation, rejection correction, and days-remaining follow-up are steady, detail-heavy work that rarely fits between front desk calls or a coder’s backlog. For practices at that point, a dedicated medical billing virtual assistant who owns the acknowledgment files and the days-remaining worklist every morning is often the most direct fix, and it’s exactly the role Care VMA builds around your existing practice management system and clearinghouse.

A trade-off worth stating plainly: if your practice bills a small, stable set of one-year payers and closes notes same-day, a formal Filing Window Budget may be more structure than you need. The framework earns its keep when payer windows are short, volume is high, or documentation lags.

Make Timely Filing the Denial You Never See

Timely filing is the one denial category that is almost entirely within your control. It doesn’t require winning an argument with a medical director or interpreting a coverage policy. It requires claims to leave the building quickly, be accepted by the payer, and be watched against the right clock.

The payer’s published limit is the outer wall. Your real protection is the internal submit-by date you set well inside it, a contract-sourced matrix, daily acceptance reconciliation, and a worklist sorted by days remaining instead of days elapsed.

If you want a second set of eyes on your payer matrix, your aging exposure, or who owns your rejection reports each morning, book a free consultation with the Care VMA team. We’ll look at your current workflow and show you where the days are going.

Frequently Asked Questions

What is the timely filing limit for Medicare?

Medicare fee-for-service claims must be filed no later than one calendar year after the date of service under 42 CFR 424.44. Limited exceptions exist for administrative error and retroactive entitlement situations, and those require supporting documentation.

Does a rejected claim count as timely filing?

No. A claim rejected by the clearinghouse or the payer’s front-end edits was never accepted, so the filing clock keeps running. Only a claim the payer accepts for processing stops the clock, which is why daily review of rejection reports matters.

Can you appeal a timely filing (CO-29) denial?

For commercial payers, you can usually appeal if you have dated proof that the payer received the claim within the window, such as a 277CA acceptance report. For Medicare fee-for-service, a claim denied for timely filing has no appeal rights, though exceptions may apply in specific circumstances.

When does the corrected claim filing window start?

It depends on the payer. Some count from the date of service, some from the original remittance date, and some apply the same deadline as the original claim. Record the start point for each payer in your deadline matrix rather than assuming it matches the initial limit.

Can a practice bill the patient if a claim is denied for timely filing?

Generally no. Most in-network contracts prohibit billing the patient for a claim denied because the provider filed late, so the balance becomes a practice write-off. Check your specific participation agreement for the exact language.