How it works
Days sales outstanding (DSO) is the average number of days between making a credit sale and collecting the cash, calculated by multiplying accounts receivable by the days in the period and dividing by credit sales. Carrying $92,000 of receivables against $280,000 of quarterly credit sales, collections average about 59 days — twenty-nine days past net-30 terms, and every one of those days is working capital lent interest-free to customers. That is the lens to hold: DSO is a loan you didn't choose to make. The calculator translates it into operating cash — daily credit sales show exactly what each recovered day releases, so cutting DSO by a week frees seven days of sales without earning a single additional order. Readings need context: consumer checkout collects in days, while B2B invoicing routinely stretches to 45-60 even against net-30 paper, so benchmark inside your channel. Two cautions refine the picture. The simple ratio averages across all invoices, letting a few giant delinquent accounts hide inside a flattering mean — the countback method traces oldest invoices and reports worse, truer numbers. And DSO shifts with mix: landing one whale customer moves it without collections changing at all, so pair the trend with who owes the balance.
Formula
DSO = (accounts receivable / credit sales) x days in period | days over terms = DSO - stated payment terms
Tips
- Invoice the day work ships — every idle day before invoicing is pure added DSO.
- Offer early-payment discounts sparingly; 2/10 net-10 costs more than it looks.
- Chase by balance size: the five largest overdue invoices are usually half the problem.
- Take deposits or milestone billing on big projects to cap exposure per client.
- Watch DSO by cohort of invoices, not just the average — averages hide whales.
Frequently asked questions
- What is days sales outstanding?
- The average number of days it takes to collect payment after a credit sale. With $92,000 owed and $280,000 of quarterly credit sales, DSO is about 59 days — the average age of your unpaid invoices.
- How is DSO calculated?
- Multiply accounts receivable by the days in the period and divide by credit sales for that period: ($92,000 / $280,000) x 90 = 59.4 days. Use only credit sales — cash sales never entered receivables and would dilute the figure.
- What is a good DSO?
- Anything consistently at or below your stated terms is strong; B2B sellers commonly run 45-60 days against net-30 paper. Judge against your own terms and history — the number that matters most is how far you drift past the terms you set.
- How can I reduce DSO?
- Invoice immediately on delivery, automate reminders at set intervals, make paying effortless with links and multiple methods, require deposits on large orders, and prioritize collection calls by invoice size. Cutting DSO releases working capital without a single new sale.
- Does DSO include cash sales?
- No. The denominator should be credit sales only, since cash sales never create receivables. Including them shrinks the ratio and makes collections look faster than they are.