π§Ύ AR Days Calculator
How fast credit sales turn into cash.
Days sales outstanding (DSO)
Estimates for planning only, not financial advice.
AR days, also called days sales outstanding (DSO) or the average collection period, is the average days between making a credit sale and collecting the cash: receivables divided by annual credit sales, times 365. With $185,000 in receivables on $2.4 million of annual credit sales, AR days are 28.1, just inside net-30 terms. Every day above your terms is an interest-free loan to customers, funded by you.
How to Use This Calculator
Enter accounts receivable (average for the period is best; ending balance works for a quick check), annual credit sales only (exclude cash sales), and your standard payment terms. The calculator returns DSO, the receivables turnover ratio, how DSO compares to terms, and the cash trapped in receivables.
Enter receivables. Use (beginning + ending) / 2 for accuracy; the ending balance alone overstates DSO after a big sales month.
Enter annual net credit sales. Exclude cash sales, or DSO will look better than it is.
Enter your payment terms to benchmark. DSO more than 10 days over terms means collections need attention. For the full working-capital picture, pair with inventory and payables analysis.
The Formulas
Turnover and DSO are reciprocals scaled by 365: our example turns receivables 13.0 times a year (2.4M / 185k), and 365 / 13.0 = 28.1 days. The "cash per day" figure, $6,575 here, is the most useful: it prices every day of DSO in dollars, so a 15-day improvement is immediately worth about $98,600 of freed cash.
Worked Example: $185,000 on $2.4M
Receivables: $185,000. Annual credit sales: $2,400,000. AR days = 185,000 / 2,400,000 x 365 = 28.1 days. Receivables turnover: 13.0x. Terms: net 30, so collections run 1.9 days inside terms: healthy. Cash per DSO day: $6,575.
Now let receivables creep to $280,000 on the same sales: DSO = 42.6 days, 12.6 days over terms, with an extra $95,000 of cash trapped ($280,000 - $185,000). That $95,000 is a silent credit line to customers, likely funding nothing productive. The fix priority: invoice timing first (free), then reminder automation (cheap), then terms enforcement (awkward but necessary).
Benchmarks by Situation
| Situation | Typical DSO | Watch when |
|---|---|---|
| Net-30 B2B services | 28-38 days | Over 45 days |
| Manufacturing / distribution | 40-60 days | Over 70 days |
| Construction (progress billing) | 50-70 days | Over 80 days |
| SaaS (annual upfront) | Under 20 days | Rising with "net" terms |
Industry norms matter because terms differ, but the terms-relative rule is universal: DSO should sit at or slightly under stated terms. A manufacturer at 55 days on net-60 terms is fine; a consultant at 55 days on net-30 terms has a collections problem wearing an industry costume.
Freeing the Trapped Cash
Work the DSO levers in ROI order. Invoice the day work ships, not at month-end: batching invoices adds half the batch cycle to DSO for free. Put payment terms and late-fee language on every invoice and contract. Automate reminders before due dates, not after; a polite day-25 nudge beats an awkward day-45 call. Offer early-pay discounts only where the math works: 2/10 net 30 implies a 36 percent annualized cost, so it is expensive financing disguised as a courtesy.
For chronic late payers, require deposits, shorten terms, or fire them: a customer who pays in 90 days on 5 percent margin is often unprofitable after carrying costs. And watch concentration: one customer at 40 percent of receivables going slow moves your whole DSO. Review the aging report monthly, act on the 30-day bucket before it becomes the 60-day bucket, and treat DSO as the cash metric it is, not an accounting curiosity. Our business loan calculator prices what that trapped cash would cost to replace with borrowing, which is usually the most persuasive slide in the collections meeting.
The DSO Improvement Playbook
Four moves reliably cut days sales outstanding. Invoice immediately: every day between delivery and invoicing is a free loan to the customer, and firms that invoice weekly instead of monthly routinely cut 10-plus days. Offer early-payment discounts only when the math works: 2/10 net 30 is a 36 percent annualized cost of capital, so take the discount yourself but think twice before offering it. Tighten terms for slow payers instead of punishing everyone.
Then systematize collections: automated reminders at 7 days before due, on the due date, and at 7, 14, and 30 days past due, with a human call at 45. Most late payment is disorganization, not distress, and a cadence fixes disorganization. Measure DSO by customer segment, because the average hides the three accounts causing half the problem. A 15-day DSO improvement on $2.4 million of receivables frees roughly $98,600 of cash: that is the budget for the collections effort, and it usually pays for itself many times over.
Estimates for planning only, not financial advice.
Frequently Asked Questions
What are AR days?
AR days (days sales outstanding, or DSO) is the average number of days between a credit sale and cash collection: (accounts receivable / annual credit sales) x 365. A company with $185,000 in receivables and $2.4M in annual credit sales has AR days of 28.1, meaning customers pay in about 4 weeks on average.
What is the AR days formula?
AR days = (average accounts receivable / net credit sales) x 365. Use average receivables ((beginning + ending) / 2) for the period, not just the ending balance, and use credit sales only, not cash sales. For quarterly figures, multiply by 90 instead of 365.
What is a good DSO?
At or below your payment terms is the benchmark: net-30 terms should produce DSO near 30. Consistently running 10-plus days over terms means collection problems or customers in distress. Compare within industry: construction and manufacturing run 40 to 60 days normally, while retail and SaaS (paid upfront) run far lower.
Why does DSO matter for cash flow?
Because sales are not cash until collected. Every extra day of DSO on $2.4M of annual sales traps about $6,575 of cash ($2.4M / 365). Cutting DSO from 45 to 30 days frees roughly $98,600 of working capital with no new sales, which is why collections is the cheapest financing a company has.
What is the difference between DSO and average collection period?
Nothing: they are two names for the same metric. DSO (days sales outstanding), average collection period, and AR days all compute (receivables / credit sales) x days in period. This calculator covers all three labels.
How do you calculate DSO with quarterly data?
Use (receivables / quarterly credit sales) x 90. Annualize carefully: multiplying one strong quarter by 4 can distort if sales are seasonal. For seasonal businesses, compare the quarter to the same quarter last year rather than annualizing, or use a trailing-twelve-month sales figure.
Should cash sales be included in DSO?
No. Cash sales never enter receivables, so including them in the denominator artificially lowers DSO and hides collection problems. If you cannot split cash from credit sales, estimate the credit share; a company doing 50 percent cash sales that includes all revenue will show half its true DSO.
What causes DSO to rise?
The usual suspects in order: customers paying late (economic stress or your invoicing is sloppy), disputed invoices sitting unresolved, sales booking revenue aggressively at quarter-end, and customer concentration (one big slow payer moves the average). Rising DSO with rising sales can also just mean growth: new customers have not paid yet.
How do you reduce AR days?
Invoice immediately (every day of delay is a day of DSO), offer small early-payment discounts (2/10 net 30 costs about 36% annualized, so use sparingly), tighten credit checks on new customers, automate reminders at 7/14/30 days overdue, and escalate disputes fast. The single highest-ROI move is usually just invoicing on time: many companies lose a week before the invoice even goes out.
DSO vs DIO vs DPO: how do they fit together?
They form the cash conversion cycle: CCC = DSO + DIO - DPO (receivable days + inventory days - payable days). DSO measures customer cash, DIO measures inventory cash, DPO measures supplier financing. Shortening DSO or stretching DPO (without damaging suppliers) shortens the cycle and frees cash. Manage all three, not just collections.