Days in AR (A/R Days)

Days in AR is a timing metric. The number answers a single question: based on current AR and recent charging volume, how many days of work sit in receivables instead of in the bank.

Lower is not always better at any cost, but sustained high days in AR usually point to problems: slow claim submission, avoidable denials, under-resourced follow up, or structural issues like payer underpayments.

How to read the number

Start with the trend, not one snapshot. Days in AR should be calculated the same way every month so the line shows direction.

Key ways to read the value:

• Compare to your own last 6 to 12 months.
• Compare to similar organizations only if the definition matches (net vs gross, trailing period used, payer mix).
• Break it down by payer and by program or level of care.

A lower number means cash is coming in closer to the date of service. A higher number means more cash is stuck in receivables. For example, a move from 35 to 50 days in AR, on 1 million dollars in monthly net charges, means roughly half a million dollars more is sitting in AR instead of in operating cash.

What makes it rise

Days in AR climbs when AR grows faster than charges or when charges drop faster than AR. Root causes tend to fall into a few buckets:

• Front-end issues: weak eligibility checks, missing authorizations, incorrect subscriber info, or wrong payer loaded to the account.
• Charge capture and coding delays: clinicians finishing notes late, missed services, lag in batching claims, or coding backlogs.
• Billing and clearinghouse problems: claims held in a work queue, clearinghouse rejections not worked, or recurring edit failures by payer.
• Denials and underpayments: growth in CO-197 or CO-16 denials, slow appeals, or no follow up on payer takebacks.
• Contracting and payment lags: payers with long payment cycles, or behavioral-health carve-out vendors that pay monthly instead of weekly.

Any change that increases the AR balance without a matching increase in daily charges will push days in AR up.

Watch the over-90 tail

Days in AR hides the shape of the aging. You can hit a decent overall number while an over-90 tail quietly grows.

Track days in AR alongside aging buckets:

• Percentage of AR over 60 and over 90 days.
• Days in AR calculated only on the over-90 slice.
• Payer and program breakdown of that over-90 AR.

A growing over-90 tail usually means claims are stuck: missing documents, ignored payer letters, no follow up on denials, or slow patient-collections workflows. Once balances age past 90 or 120 days, recovery rates drop and write-offs increase, so the over-90 tail is where real cash loss hides.

Beyond the main formula, a few variations are worth knowing. Each answers a slightly different question.

Imagine a behavioral-health group with the following for the quarter ending June 30:

• Total AR on June 30: 1,200,000 dollars (net of contractuals)
• Total net charges April 1 through June 30 (91 days): 2,730,000 dollars

Average daily net charges = 2,730,000 ÷ 91 = 30,000 dollars.

Net days in AR = 1,200,000 ÷ 30,000 = 40 days.

Now split by payer:

• Commercial / carve-out AR: 900,000 dollars; last 90 days net commercial charges: 1,800,000 dollars → 20,000 dollars per day → 900,000 ÷ 20,000 = 45 days.
• Medicaid AR: 300,000 dollars; last 90 days net Medicaid charges: 900,000 dollars → 10,000 dollars per day → 300,000 ÷ 10,000 = 30 days.

Overall days in AR looks acceptable at 40 days, but the commercial line at 45 days is dragging it up. That points you toward fixing authorization, documentation, or underpayment issues specific to commercial and carve-out payers before cash gets tighter.

• Including credit balances in total AR, which lowers days in AR and makes performance look better than it is. For example, posting a large refund batch to AR instead of a separate liability account will artificially reduce the metric.
• Using gross charges instead of net charges without labeling the metric, then comparing to benchmarks based on net days in AR. The practice looks like it is collecting in 30 days when peers are reporting 40 net days in AR on a comparable payer mix.
• Changing the trailing period used for the denominator (for example, using 30 days of charges in some months and 90 in others) so the trend line becomes meaningless, especially around seasonality or a big program launch.
• Mixing behavioral-health programs with very different billing patterns into one number, such as combining long-stay residential per-diem AR with fast-turn outpatient visits, which hides real trouble spots in specific programs or payers.
• Failing to exclude non-patient AR like grants, capitation prepayments, or internal balances from the total AR input, which can inflate the metric and send the team chasing balances that are not claim-based or collectible in the usual workflows.

Behavioral-health AR often runs higher than a general medical practice because of longer stays and per-diem billing. In residential treatment, charges stack up daily, but a claim may not go out until discharge or until the clinical team locks a weekly or monthly bundle. Days in AR will look high even when collection rates are healthy, simply because charges accelerate before a full clean claim reaches the payer.

Segmenting days in AR by program level is essential. At minimum, split residential, PHP, IOP, and outpatient. A 55-day residential line combined with a 25-day outpatient line can average into something that looks fine on paper, even though payers are taking 60 to 90 days to pay per-diem residential claims.

Carve-out behavioral-health payers and specialized Medicaid managed-care plans also skew the picture. Some pay once or twice per month in large batches. That pattern creates sawtooth AR volume that raises days in AR between payment runs. Without payer-level days in AR, the team may chase the wrong root cause when the real issue is cycle timing or missing utilization-review documentation.

Finally, concurrent authorization rules and clinical documentation gaps hit behavioral health harder. When a payer denies days mid-stay for lack of medical necessity evidence, AR can sit in limbo waiting for appeals. Days in AR will rise on a relatively small number of high-dollar authorizations, so tracking the over-90 tail by program and by payer becomes a survival tactic, not a luxury metric.

AI can handle the monitoring and grunt work around days in AR so humans can focus on fixing the causes. An agent can watch AR, charges, and aging buckets daily, recalculate days in AR by payer and program, and surface spikes or patterns, such as a sudden rise in over-90 AR on one Medicaid MCO. An agent can also tie those spikes back to denial codes, payment lags, or missing documents so the team sees where dollars are actually stuck.

Supabill's claims-scrubbing agent can hold payer-specific rules, flag claims likely to deny for CO-197 or CO-16 before submission, and cut future AR days by preventing avoidable rework. The denials agent can read every 835, classify CARC and RARC codes, and show which payers and services are driving the heaviest AR tail. AI will not negotiate with payers, manage delicate provider-payer relationships, or decide when to escalate a pattern to contracting, so humans still have to own clinical conversations, appeals strategy, and structural fixes. AI handles the volume and pattern-recognition; people drive the changes that move the metric.

Should days in AR be calculated using gross or net charges?

For most behavioral-health organizations, net days in AR is more meaningful. Net charges remove expected contractual adjustments and charity, so the denominator lines up with the amount you actually expect to collect. Gross days in AR will usually report a lower number and can create a false sense of speed, especially with high contractual discounts on out-of-network or Medicaid services. If gross charges are used for internal reasons, the metric should be labeled clearly and never compared directly to net-based benchmarks or peers that report net days in AR. Source

How often should days in AR be measured for a behavioral-health practice or facility?

Monthly is the minimum for formal reporting, but a weekly view is useful if charge volume is high or cash is tight. Behavioral-health programs with long stays and per-diem billing benefit from watching days in AR around key events: month end, large discharge weeks, or payer rate changes. The important part is to keep the method consistent: same trailing period, same definition of net charges, and the same inclusion or exclusion rules for specialty programs and non-patient AR. Source

What is a good target for days in AR in behavioral health?

Better performers across ambulatory and facility settings often keep total AR under roughly 40 days, based on MGMA and HFMA MAP Keys benchmarking, but payer and program mix matter. A residential-heavy behavioral-health provider with state Medicaid and carve-out vendors may run slightly higher days in AR than a pure outpatient group on mostly commercial plans, even with excellent processes. The goal is to combine external benchmarks with your own trend and to push each payer-program segment toward faster payment without creating excessive write-offs or staff burnout. Source

How does days in AR relate to the aging report and over-90 balances?

Days in AR gives a single timing number, while the aging report shows the shape of the AR by age buckets. A facility can post a respectable 40 days in AR while 20 percent or more of AR sits in the over-90 bucket, which signals elevated write-off risk. Because behavioral-health claims often have long episodes and concurrent-review rules, the over-90 portion can represent a small number of large claims that are clinically or contractually complex. Monitoring over-90 days in AR and the percentage of AR over 90 alongside the headline days in AR number provides a clearer view of true collection risk.

Why did days in AR spike after opening a new residential program even though cash receipts look strong?

New or expanded residential programs often increase daily net charges quickly as census ramps, while claims and payments lag behind. If claims are held until discharge or until a weekly or monthly billing cycle, AR accumulates faster than payments arrive. The metric will show a spike in days in AR that may not indicate a structural problem, just a timing shift. Segmenting days in AR by program will show that outpatient remains stable, while the residential line rises temporarily. If residential days in AR stay high after the program matures, that is when to investigate authorizations, documentation, and payer-specific payment cycles.

• MGMA
• HFMA — MAP Keys