Accounts Receivable Calculator
Calculate Days Sales Outstanding (DSO), AR turnover and the true cost of slow-paying customers.
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DSO and AR turnover: reading your receivables health
Days Sales Outstanding tells you how long the average invoice sits unpaid. For most U.S. small businesses on net-30 terms, healthy DSO is 30 to 45 days. Atradius and Dun & Bradstreet payment studies put the cross-industry average near 40 days, with construction and B2B services routinely above 60 and retail or SaaS (paid upfront) under 10. A DSO that runs more than 50% past your stated terms means your collections process, not your customers, is the problem.
The cash impact is bigger than most owners think. Every day of DSO ties up one day of revenue in working capital. A business doing $1.2M per year carries about $3,300 of cash per DSO day. Cutting DSO from 55 to 40 days frees roughly $50,000 of permanent working capital without selling anything extra or borrowing a cent.
The two formulas this calculator computes
DSO = (accounts receivable / annual credit sales) x 365 AR turnover = annual credit sales / average AR balance (higher turnover = faster collection)
Worked example: $1.2M services firm
Annual credit sales: $1,200,000 Current AR balance: $150,000 DSO = (150,000 / 1,200,000) x 365 = 45.6 days AR turnover = 1,200,000 / 150,000 = 8.0x per year Target: 38 days -> AR of $125,000 Cash freed: ~$25,000
What actually lowers DSO
Invoice the day work completes, not month-end (saves 10 to 15 days on its own). Take deposits or progress billing on anything above a few thousand dollars. Offer a small early-pay discount (2/10 net 30 costs you 2% but works); charge stated late interest and actually apply it. Run an aging report weekly and call, not email, anything past 45 days. Require card or ACH on file for repeat clients. And credit-check new B2B customers above a threshold: one $40,000 write-off erases the margin on months of sales.
Watch the aging mix, not just the average. A 42-day DSO made of clean 40-day payers is fine; the same DSO with 20% of dollars past 90 days is a write-off risk wearing a healthy average. Receivables past 90 days collect at roughly 50 cents on the dollar according to commercial collection agency data.
Benchmarks from Atradius Payment Practices Barometer and D&B small business credit data through 2025. Educational estimates, not accounting advice.
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Frequently Asked Questions
What is Days Sales Outstanding (DSO)?
DSO measures the average number of days it takes to collect payment after a sale. DSO = (AR Balance / Annual Revenue) x 365. A DSO of 45 means you wait 45 days on average to get paid. Lower DSO means faster cash collection. Compare your DSO to your payment terms: if terms are Net 30 but DSO is 55, customers are paying late.
What is a good DSO for a business?
A good DSO is close to your stated payment terms. If you offer Net 30, aim for DSO of 30-40 days. Industry benchmarks vary: professional services 40-60 days, manufacturing 45-55 days, retail near zero (cash sales). DSO above 60 days for Net 30 terms signals a collections problem that is draining cash flow.
How do I reduce DSO and improve cash flow?
Effective strategies: invoice immediately upon delivery (not at month end), offer early payment discounts (2/10 Net 30 = 2% discount if paid within 10 days), automate payment reminders at 7, 14, and 30 days past due, require deposits upfront for large projects, accept credit cards, and enforce late payment fees consistently.