Days in A/R and net collection rate: how to calculate them

The days in A/R formula

Days in A/R = total A/R ÷ average daily charges

• Total A/R: all open balances on claims and patient accounts on the report date, here $214,600.
• Average daily charges: the charges of a recent period divided by its days. Three months is the most common window: 529,800 ÷ 92 = $5,759.

Result: 214,600 ÷ 5,758.70 = 37.3 days. It reads as "the practice has 37 days of charges waiting to be paid". Some practices use six months of charges to smooth seasonal swings. Whatever you choose, keep the window fixed so the trend means something.

Worked example: A/R and collections of a medical practice

Rows 2 to 6 calculate average daily charges, rows 9 to 16 age the A/R and calculate days in A/R, and rows 19 to 27 calculate the collection rates of the settled first half year. The practice and all figures are fictional and synthetic.

Worked example: A/R and collections of a medical practice

	A	B	C
1	Month	Gross charges	Days
2	July	182,000	31
3	August	176,500	31
4	September	171,300	30
5	Total, last 3 months	529,800	92
6	Average daily gross charges	5,759
7
8	A/R aging bucket at 30 Sep	Balance	Share
9	0–30 days	98,400	45.9%
10	31–60 days	52,300	24.4%
11	61–90 days	27,800	13.0%
12	91–120 days	15,600	7.3%
13	Over 120 days	20,500	9.6%
14	Total A/R	214,600	100%
15	A/R over 90 days	16.8%
16	Days in A/R = total A/R ÷ average daily charges	37.3
17
18	Collections, January to June (settled)	Amount
19	Gross charges	1,080,000
20	Contractual adjustments	432,000
21	Controllable write-offs (late filing, no authorization)	19,400
22	Payments received (payers and patients)	612,500
23	Gross collection rate = payments ÷ charges	56.7%
24	Net collection rate = payments ÷ (charges − contractual)	94.5%
25	Target net collection rate	96%
26	Dollars missing to target	9,580
27	Wrong: write-offs also deducted	97.4%

Fictional practice with synthetic figures. Educational only, not billing, coding or legal advice.

Gross or net: keep both sides on the same basis

A/R can be stated at gross charges (the fee schedule) or net of expected contractual adjustments. Charges can be gross or net too. Mixing them, for example net A/R against gross charges, makes days in A/R look far better than it is. Use gross A/R with gross charges, or net A/R with net charges. Many practices also remove credit balances from A/R first, because overpayments owed back to patients or payers are not money to collect.

Commonly quoted targets for physician practices are below about 35 to 40 days, with under 50 as an upper limit. Specialty, payer mix and how quickly claims go out all move the number, so compare it with your own trend first.

A/R aging and A/R over 90 days

Days in A/R is an average. The aging report shows where the money sits: open balances grouped by age, usually 0–30, 31–60, 61–90, 91–120 and over 120 days, measured from the date of service (or the billing date, used consistently). In Excel, an approximate lookup on the age finds the bucket.

The key ratio is A/R over 90 days = balances older than 90 days ÷ total A/R. Here (15,600 + 20,500) ÷ 214,600 = 16.8%, above the 10 to 15% that is often quoted as a target. Weight it by dollars, not by the number of claims. Old claims are the ones that run into filing and appeal deadlines and become write-offs.

The net collection rate formula

Net collection rate = payments ÷ (gross charges − contractual adjustments)

Contractual adjustments are the difference between the fee schedule and what payers allow under their contracts. Nobody could ever collect them, so they come out of the denominator. What remains is the money the practice was entitled to. In the example: 612,500 ÷ (1,080,000 − 432,000) = 612,500 ÷ 648,000 = 94.5%.

The gross collection rate, payments ÷ gross charges, is only 56.7% here. It mostly reflects how high the fee schedule is set and says little about billing performance. Benchmarks for the net rate are commonly quoted at about 95 to 99%.

Keep controllable write-offs in the denominator

The practice also wrote off $19,400 of claims that were filed too late or lacked a prior authorization. That money was collectible and was lost, so it stays in the denominator and lowers the rate. Deducting it as well would raise the rate to 97.4% and make a billing office that loses money look excellent.

Measure the rate on a period whose claims are settled, here January to June, because recent charges still in A/R pull it down for a while. Turn the gap into dollars to make it concrete: 96% × 648,000 − 612,500 = $9,580 missing to target.

Days in A/R vs DSO

Days in A/R is the healthcare name for days sales outstanding (DSO): receivables divided by average daily sales or charges. The difference is mainly the vocabulary and the gross versus net question, which matters far more in healthcare because contractual adjustments are so large. Both feed the cash conversion cycle.

Common mistakes

• Mixing gross and net. Net A/R divided by gross daily charges understates days in A/R. Put both on the same basis.
• Deducting controllable write-offs from the denominator. Late filing and missing authorizations were collectible money. Only contractual adjustments come out.
• Measuring collections on recent months. Charges still in A/R lower the rate. Use a period whose claims are settled, or a rolling 12 months lagged by a quarter.
• Counting claims instead of dollars. A/R over 90 days is weighted by balance. Ten small old claims matter less than one large one.
• Changing the charge window. Switching between 3 and 6 months of charges moves days in A/R without any change in collections.
• Leaving credit balances in A/R. Overpayments to refund reduce total A/R and hide slow accounts. Report them separately.