DSO Calculator — Days Sales Outstanding

Enter accounts receivable, credit sales and the period length. Get DSO in days, how it sits against the terms you actually invoice on, and the cash a shorter collection cycle would release. Every number here is your input or arithmetic from it — the figures you enter are never transmitted.

Closing (or average) AR balance for the period — trade receivables only.
Invoiced sales only. Cash and card sales settled at the point of sale never touch AR — leave them out.
Must be the exact window those credit sales were made in.
Used only to compare your DSO with your own terms. Leave blank or 0 to skip.

How the math works

Days Sales Outstanding: DSO = (Accounts Receivable ÷ Credit Sales) × Period Days

Average daily credit sales: daily = Credit Sales ÷ Period Days

Cash freed by collecting faster: cash released = (Credit Sales ÷ Period Days) × Days of DSO reduction

Gap against your own terms: gap = DSO − your Net term (in days), and cash in the gap = daily × gap

Worked example — these are the values already loaded in the form above, so pressing Calculate DSO reproduces every line:

A business closes a quarter with $90,000 of accounts receivable on $180,000 of credit sales over a 90-day period.

  • DSO = (90,000 ÷ 180,000) × 90 = 0.5 × 90 = 45.0 days
  • daily = 180,000 ÷ 90 = $2,000 per day
  • cash released by 5 days = 2,000 × 5 = $10,000
  • Invoicing on Net 30: gap = 45.0 − 30 = 15.0 days, and cash in the gap = 2,000 × 15 = $30,000

Read that last line literally: $30,000 of this business's own money is sitting in receivables beyond the term it agreed with its customers.

Getting the two inputs right

  • Credit sales, not total sales. Anything collected at the point of sale never enters AR. Putting it in the denominator drags DSO down without a single invoice being paid sooner.
  • Same window, both figures. A quarter-end AR balance belongs with that quarter's credit sales and Period Days = 90. Mixing a year-end balance with one month of sales produces a number that means nothing.
  • Same tax basis. AR balances usually include sales tax or VAT; revenue figures usually exclude it. Divide one by the other and DSO comes out overstated. Use both gross or both net.
  • Same currency. DSO is a count of days, so the currency cancels out of the division — but only if both inputs are in one currency. Convert first if you invoice in several.
  • AR net of what you will not collect. If a balance is written off or provided against as doubtful, leaving it in AR inflates DSO and hides the real collection speed.

How to read your DSO — against your own terms, not someone else's average

DSO is one number with one honest interpretation: over the period you chose, a dollar of credit sales sat in receivables for roughly this many days on average. Turning that into a verdict needs a reference point, and the only reference this page will give you is one you already own.

  • Compare it with the terms you actually invoice on. If your terms are Net 30 and your DSO is well above 30, receivables are on average aging past the term you agreed — the excess days are the slack between what your contract says and what your bank account sees.
  • DSO at or below your term is arithmetically possible when deposits, prepayments or early payers pull the average down. It means the typical invoice is settling inside the window you set.
  • Put a price on the gap. Multiply the excess days by average daily credit sales (daily × gap) and the abstraction becomes a cash figure — the calculator does this for you whenever you enter a Net term.
  • An average hides its own tail. A handful of very large, very late invoices can lift DSO while most customers pay on time. Before treating a high DSO as a company-wide problem, open the aged receivables list and look at which invoices are carrying it.
  • The trend beats the level. Same formula, same period length, same definition, month after month. A DSO moving up tells you something even when you have no idea what the "right" level is.

We publish no "industry average DSO" here on purpose. Any single benchmark number blends businesses with different payment terms, customer mixes, credit policies and seasonality, so it cannot tell you whether your receivables are healthy. Your own terms and your own trend can.

Scope note. DSO is a management metric, not a figure defined by an accounting standard — there is no single authoritative version of it, so state which method you used whenever you report it. This page implements the standard (simple) formula shown above. Some finance teams instead use a countback, or "exhaustion", method that unwinds the receivables balance month by month against each month's sales; it responds differently to a seasonal sales curve. Neither is more correct in the abstract. Nothing here is accounting, tax or financial advice — for statutory reporting, follow your accounting framework and your accountant.

DSO FAQ

What is a good DSO?

There is no single 'good' DSO, and this page deliberately publishes no industry-average benchmark, because any such average blends businesses with different payment terms, customer mixes and seasonality — it cannot tell you whether your receivables are healthy. Use two references you actually own instead. First, your own terms: if you invoice Net 30 and your DSO sits well above 30, the average invoice is being settled after the term you agreed. Second, your own trend: run the same formula over the same period length every month — a DSO that is climbing means cash is moving more slowly than it did, whatever the level.

Should I use total sales or credit sales in the formula?

Credit sales only — the sales you invoiced and are waiting to be paid for. Cash and card sales collected at the point of sale never enter accounts receivable, so including them inflates the denominator and pushes DSO down without collections having improved. Two matching rules go with it: the sales figure must cover exactly the period you selected, and the AR balance and the sales figure must be on the same basis for sales tax or VAT. An AR balance that includes tax divided by sales that exclude it overstates DSO.

Which period length should I use — 30, 90 or 365 days?

Whichever period your sales figure covers: the period days must be the exact window those credit sales were made in, or the result is meaningless. Beyond that it is a trade-off. A 365-day period smooths seasonality and moves slowly; a 30-day period reacts fast, but one large invoice or a quiet month can swing it. A quarter (90 days) sits in the middle. What matters most is picking one and keeping it, so that month-to-month numbers are comparable.

How much cash does cutting DSO actually free up?

Multiply average daily credit sales by the number of days you cut: (credit sales / period days) x days of reduction. With $180,000 of credit sales over 90 days, average daily credit sales are $2,000, so a 5-day reduction releases 2,000 x 5 = $10,000. Two caveats. It is a one-time release of cash that was already yours but tied up in receivables — not extra profit and not recurring revenue. And it only materialises if the sales rate holds and the faster collection sticks.