Days in AR is the average number of days it takes to collect what you bill. Divide total accounts receivable by average daily charges. Under about 40 days is commonly treated as healthy, and above 50 is a warning sign that cash is stuck somewhere in the revenue cycle.
1. What days in AR measures
Days in accounts receivable (AR) shows how many days of charges are sitting uncollected. It is the single most watched speed metric in medical billing because it captures problems across the whole cycle: slow charge entry, claim errors, unworked denials, slow posting, and patient balances.
2. The formula, with an example
Average daily charges = Gross charges for the period ÷ Number of days in the period (90 days is common).
| Step | Example |
|---|---|
| Total AR today | $600,000 |
| Gross charges, last 90 days | $1,350,000 |
| Average daily charges | $1,350,000 ÷ 90 = $15,000 |
| Days in AR | $600,000 ÷ $15,000 = 40 days |
Some organizations use net (expected) charges instead of gross charges. Either works if you are consistent, but do not compare a gross-based number to someone else's net-based benchmark.
3. Days in AR calculator
4. Benchmarks
| Days in AR | Commonly read as |
|---|---|
| Under 30 | Excellent; fast collections |
| 30 to 40 | Healthy for most practices |
| 40 to 50 | Room to improve; look for a specific bottleneck |
| Over 50 | Cash is stuck; denials, aged AR, or charge lag likely need attention |
These are commonly cited industry ranges, not fixed rules. Specialty, payer mix, and patient balance share all move the number. Pair days in AR with the share of AR over 90 days: a practice can show a decent average while a growing pile of old claims heads toward its filing limits.
5. What drives days in AR up
- Charge lag: days between the visit and charge entry. Every day of lag adds to AR. See missed charge capture.
- Front-end errors: eligibility and demographic mistakes that cause rejections and denials like CO-16.
- Unworked denials: denials that sit in a queue instead of being fixed or appealed within days.
- Slow payment posting: payments received but not posted make AR look older than it is. See 835 payment posting automation.
- Credentialing gaps: claims held or denied because a provider is not yet enrolled with the payer.
- Patient balances: deductibles and coinsurance that are billed late or followed up slowly. See PR-1.
6. How to lower days in AR
- Cut charge lag to a set target, for example 2 business days, and report it weekly by provider.
- Raise your clean claim rate with eligibility checks and scrubber edits built from your own denial history.
- Work denials within 48 to 72 hours of the remittance, sorted by dollars and by filing deadline.
- Work aged AR by value and deadline, not oldest first.
- Automate payment posting so AR reflects reality the day money arrives.
- Collect patient responsibility at the visit and keep cards on file with consent.
7. Mistakes that distort the number
- Large write-offs lower days in AR without collecting anything. Watch adjustments alongside the metric.
- Credit balances netted against AR make it look smaller than it is.
- Mixing methods: changing from gross to net charges, or from 90 to 30 days, breaks the trend line.
- Ignoring the mix: an average across payers can hide one payer that is far behind.
For a full health check of a billing operation, see the RCM company health check.
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