A dermatology practice owner told us his days in AR was 28 and he was pleased with it. His billing manager, in the same meeting, said it was 41. They were looking at the same practice on the same day. He was using a report that excluded credit balances and anything over 120 days, because the previous billing company had set the report up that way. She was using everything. Neither number was wrong. One of them was useful.
Days in accounts receivable, usually shortened to days in AR, is meant to answer a simple question: on average, how long does it take the practice to turn a charge into cash? It is the first number most consultants ask for and the first one most billing companies put on a dashboard. It is also easy to manipulate, easy to misread, and, on its own, almost useless for deciding what to do next. This article covers how to calculate days in AR the standard way, the adjustments that make it lie, the ranges we actually see in independent practices, and the two splits that turn it into an action list.
We are writing this for physicians who see the number monthly and are not sure whether to worry, and for managers who inherited a report and want to know what it is doing.
Key takeaways
- Days in AR equals total outstanding receivables divided by average daily charges, with average daily charges taken over the trailing 90 days.
- Excluding credit balances, old balances or patient balances lowers the number without improving anything; use gross AR and say so.
- Independent practices we audit usually run between 30 and 50 days; below 30 is excellent and above 60 means claims are stalling somewhere specific.
- The total is a symptom; the payer split and the aging buckets tell you which claims to work.
- Track it monthly on the same day with the same definition, because a changed definition looks exactly like a changed result.
How to calculate days in AR
The formula has two inputs. Total accounts receivable is the sum of all open balances owed to the practice at a point in time, from payers and from patients. Average daily charges is total gross charges over a recent period divided by the number of calendar days in that period. Divide the first by the second and you have days in AR.
The standard period for the charge average is the trailing 90 days, which smooths out a slow week or a holiday without being so long that a change in volume disappears. Take a fictional three-provider practice on January 31. Gross charges for November, December and January were $312,000, $288,000 and $335,000, a total of $935,000 over 92 days, so average daily charges are $10,163. Total AR on January 31 is $421,000. Days in AR is 421,000 divided by 10,163, or 41.4 days.
Two decisions inside that calculation matter. Use gross charges, not expected payments, in the denominator, because AR is carried at gross charges in most practice management systems. Mixing gross AR with net charges inflates the number badly. And use the same day each month, ideally the last calendar day after the month-end close, so that the timing of a large payer payment does not swing the result.
| Input | Value | Source report |
|---|---|---|
| Gross charges, trailing 92 days | $935,000 | Charge summary by month |
| Average daily charges | $10,163 | Charges divided by 92 |
| Total open AR, all payers and patients | $421,000 | AR aging summary, gross, including credits |
| Days in AR | 41.4 | AR divided by average daily charges |
The two ways the number gets distorted
The first is what the dermatology owner's report was doing: excluding things from the numerator. Credit balances are negative AR, and netting them against positive balances makes the total look smaller. Balances over 120 days are sometimes dropped on the theory that they are "not real AR." Patient balances are sometimes excluded because "we can't control those." Each exclusion lowers the number. None of them collects a dollar. We report gross AR including credits, and separately show the credit balance total, because a large credit balance is its own problem (and a compliance one, given Medicare's 60-day rule on refunding overpayments).
The second distortion is on the other side: writing off aggressively right before the measurement date. A practice that adjusts off every balance over 180 days on the last day of the month will show a wonderful days in AR and a terrible write-off rate, and the second number is rarely on the dashboard. Days in AR should always be read next to the adjustment total for the month. If AR fell and adjustments rose, nothing improved.
There is a legitimate version of the metric that nets out things you truly cannot collect yet, such as claims held for a provider whose enrollment is pending. If you use it, label it as adjusted days in AR and report the gross figure alongside. The problem is never the adjustment. The problem is the unlabeled adjustment that a new owner or manager inherits without knowing it exists.
What a good number looks like
Published benchmarks from practice management associations have long put the target under 35 days for most specialties and under 30 for primary care, with anything above 50 as a warning. In the practices we audit, well-run primary care and pediatrics run 25 to 35 days, because visits are frequent, claims are simple and copays are collected at the desk. Surgical and procedural specialties run 35 to 50, because prior authorizations, global periods and larger balances slow everything down. Practices with heavy Medicaid managed care or workers' compensation volume run higher through no fault of their own, since those payers are slow.
So the answer to "is 41 good" is that it depends on specialty and payer mix, and the more useful question is which direction it has moved over six months and why. A practice at 41 that was at 34 two quarters ago has a problem even if 41 is within range. A practice at 45 with a 30 percent Medicaid mix and falling may be doing well.
The number also has a floor set by payer behavior. Most commercial payers pay clean electronic claims in 14 to 30 days. Medicare pays clean claims on day 14 at the earliest under the payment floor. So even a perfect practice carries roughly two to three weeks of AR at all times. Anything above that is claims that were submitted late, rejected, denied, pended, or balances that moved to patients and are waiting on statements.
Splitting it so it points at something
The total days in AR is a temperature reading. The diagnosis needs two splits. The first is by payer. Run the same calculation with each payer's AR over that payer's share of charges. In the fictional practice, Medicare might be at 24 days, the largest commercial plan at 31, a Medicaid managed care plan at 68, and patient balances at 74. Now the 41 has a shape. The Medicaid plan and the patient balances are carrying it, and those need different fixes: the Medicaid plan probably has an enrollment or authorization issue, and the patient balances need a statement cycle review.
The second split is the aging buckets: 0 to 30, 31 to 60, 61 to 90, 91 to 120 and over 120 days, expressed as a percentage of total AR. A healthy practice has most of its AR in the first bucket and less than 15 percent over 90 days. When the over-90 share climbs past 20 to 25 percent, the practice is not following up on denials, or it is letting patient balances age without a collection step. When the 31 to 60 bucket is oddly large, claims are being submitted late or sitting in a rejection queue.
Put those two splits on one page with the total, and the monthly meeting writes itself. Which payer moved? Which bucket grew? Then pull the top 20 claims by dollar in the worst cell and work them. If the practice does not have a report that does this, the RCM audit we run builds it from the raw AR detail, and once it exists most practice management systems can reproduce it monthly.
Days in AR is not the same as cash
One last caution. Days in AR measures how long money is outstanding, not how much of it arrives. A practice can have excellent days in AR and poor collections if it writes off too readily, undercodes, or never bills for services that were performed. Charges that never became claims are not in AR at all, so they cannot lengthen it. Underpayments that were posted as paid in full are closed, so they do not lengthen it either. The metric only sees what was billed and is still open.
That is why we never report it alone. Net collection rate (payments divided by charges less contractual adjustments) tells you how much of what you were owed you collected. Charge lag tells you how long the encounter took to become a claim. Clean claim rate tells you how much of the AR is there because of rework. Days in AR sits in the middle of that set. Read together they describe the revenue cycle. Read alone, days in AR mostly describes the report settings.
Questions we hear
Our billing company reports days in AR at 22. Is that believable?
It is possible for a primary care practice with strong front desk collections and mostly commercial and Medicare patients. Ask for the definition: gross or net AR, credits included or excluded, and whether balances over a certain age are dropped. If the adjustment total rose in the same months the AR fell, the number is being managed rather than earned.
Should patient balances be in the calculation?
Yes, in the total. Patient balances are real receivables and excluding them hides the practice's single slowest payer. Report them as their own line in the payer split so the payer AR and the patient AR can be read separately.
How quickly can days in AR come down?
It depends on where the AR is. Working denied claims in the 61 to 120 day buckets moves the number within one to two months as they pay or are appropriately adjusted. Fixing charge lag or clean claim rate takes longer to show, because it acts on new claims. Nobody should promise a specific number by a specific month; the honest answer is that the payer split tells you which fixes are quick and which are slow.
What to do this week
- Pull the AR aging summary and the trailing 92-day charge total as of the last day of the month, and compute days in AR on gross AR including credits.
- Write the definition you used at the top of the report so nobody can change it silently later.
- Run the same calculation by payer and identify the two payers, or patient balances, with the highest days.
- Calculate the percentage of AR over 90 days and compare it to your last three months.
- Pull the 20 largest open claims from the worst payer and aging cell, and assign them for follow-up this week.
