Days in AR, Explained
Days in AR tells you how long your money sits unpaid after the work is done. Here is the formula, a worked example, what the aging buckets reveal, and the levers that bring the number down.
Ask a practice manager how billing is going and you will hear about claims, denials and individual payers. Ask for one number that summarizes all of it, and that number is days in accounts receivable — days in AR. It measures the average time between providing a service and getting paid for it, and it reacts to almost everything in the revenue cycle: slow charge entry, rejections, denials, lazy follow-up.
The days in AR formula
The standard calculation is:
Days in AR = Total accounts receivable ÷ Average daily charges
Average daily charges are usually your gross charges over the last 90 days (some practices use 6 months for stability) divided by the number of days in that period.
A worked example
Suppose a practice billed $270,000 in gross charges over the last 90 days. Average daily charges = $270,000 ÷ 90 = $3,000. If total AR on the books today is $126,000, then days in AR = $126,000 ÷ $3,000 = 42 days. The interpretation: on average, 42 days of work are sitting unpaid at any moment. (These figures are an illustration of the arithmetic, not a benchmark.)
What is a "good" days in AR?
It depends on specialty and payer mix — a practice heavy in slow-paying payers will run higher than one paid mostly by fast commercial plans. Many practices aim to keep the figure in the 30s or below, and treat a sustained climb past 40–50 as a warning sign worth investigating. The trend matters more than any single month's number, which is why days in AR belongs on a monthly dashboard next to the KPIs in our revenue cycle management guide.
Read the aging buckets, not just the average
| Bucket | What it should look like | Warning sign |
|---|---|---|
| 0–30 days | The largest bucket — current claims working through payers | Shrinking while older buckets grow: new claims are stalling |
| 31–60 days | A moderate share: slow payers and first-pass denials in progress | Growing faster than the 0–30 bucket |
| 61–90 days | Small: appeals and stubborn claims | Anything routine landing here means follow-up is behind |
| 91–120 days | Very small | Claims here are approaching payer appeal and filing deadlines |
| 120+ days | As close to zero as possible | Every dollar here is at real risk of becoming a write-off |
How to reduce days in AR
- Enter charges fast. A claim cannot be paid before it exists; a 24–48 hour charge-entry standard removes days before the cycle even starts.
- Verify eligibility and authorizations up front. The fastest claim is the one that never gets denied — see the front-end steps in our billing process guide.
- Work rejections daily. A rejected claim is not yet in the payer's system; every day it waits is a day added straight onto AR.
- Follow up on a schedule, by bucket and payer. Systematic AR follow-up strategies — status checks, escalation paths, documented payer calls — beat random effort.
- Attack denials by root cause. Recurring denial reasons fixed once remove whole categories of delay.
- Bill patients promptly. Patient balances are part of AR too; clear, timely statements collect faster than quarterly surprises.
Practices that cannot give AR this level of weekly attention often hand the whole worklist to a dedicated accounts receivable management team, where follow-up cadence and escalation are the entire job.