# What is my DSO?

Computes days sales outstanding (DSO), the average days to collect a credit sale, from credit sales and accounts receivable.

- Page: https://www.acalculator.org/finance/dso-calculator
- JSON spec: https://www.acalculator.org/finance/dso-calculator.json
- Version: 1ac321eb4554

## Default answer

Example with the default inputs (Net credit sales $400,000.00, Accounts receivable at the start $70,000.00, Accounts receivable at the end $90,000.00, Days in the period 365): With average receivables of $80,000.00 against $400,000.00 of credit sales over 365 days, it takes 73 days on average to collect a credit sale.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| sales | Net credit sales | Sales on credit for the period, after returns and allowances. Use net sales if credit sales are not shown. |
| bar | Accounts receivable at the start | Accounts receivable at the start of the period. Leave empty to use the ending balance alone. |
| ear | Accounts receivable at the end | Accounts receivable at the end of the period. |
| days | Days in the period | The days the sales cover: 365 for a year, 90 or 91 for a quarter, 30 or 31 for a month. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| dso | Days sales outstanding (DSO) | Average accounts receivable ÷ net credit sales × days in the period. |
| turnover | Accounts receivable turnover | Net credit sales ÷ average accounts receivable for the period. |
| average | Average accounts receivable | (Beginning + ending accounts receivable) ÷ 2, or the ending balance when no beginning is given. |

## Method

Average accounts receivable = (beginning + ending) ÷ 2 (ending alone when no beginning is given). Turnover = net credit sales ÷ average accounts receivable. DSO = average accounts receivable ÷ net credit sales × days in the period = days ÷ turnover.

## Assumptions

- The credit sales cover the period whose days you enter, and the two balances are from its start and end.
- Arithmetic is exact on the typed decimals; both results show to 2 decimals, halves up.

## Worked examples

1. sales = $400,000.00, bar = $70,000.00, ear = $90,000.00, days = 365 gives dso = 73, turnover = 5, average = $80,000.00. Source: OpenStax, Principles of Accounting, Volume 1, 9.3 Determine the Efficiency of Receivables Management Using Financial Ratios (number of days’ sales in receivables = 365 ÷ (net credit sales ÷ average accounts receivable)). https://openstax.org/books/principles-financial-accounting/pages/9-3-determine-the-efficiency-of-receivables-management-using-financial-ratios: 400,000 ÷ 80,000 = 5 times.
2. sales = $550,000.00, bar = $50,000.00, ear = $80,000.00, days = 365 gives dso = 43.136364. Source: OpenStax, Principles of Accounting, Volume 1, 9.3 Determine the Efficiency of Receivables Management Using Financial Ratios (number of days’ sales in receivables = 365 ÷ (net credit sales ÷ average accounts receivable)). https://openstax.org/books/principles-financial-accounting/pages/9-3-determine-the-efficiency-of-receivables-management-using-financial-ratios: 43.14 days (rounded).
3. sales = $90,000.00, bar = $25,000.00, ear = $35,000.00, days = 90 gives dso = 30, turnover = 3. Source: OpenStax, Principles of Accounting, Volume 1, 9.3 Determine the Efficiency of Receivables Management Using Financial Ratios (number of days’ sales in receivables = 365 ÷ (net credit sales ÷ average accounts receivable)). https://openstax.org/books/principles-financial-accounting/pages/9-3-determine-the-efficiency-of-receivables-management-using-financial-ratios (formula with the quarter's 90 days).

## FAQ

### What is DSO?

Days sales outstanding (DSO) is the average number of days a company waits to be paid after a sale on credit. A DSO of 45 means customers pay, on average, 45 days after the sale.

### How do I calculate DSO?

Divide the average accounts receivable by net credit sales and multiply by the days in the period. Billie's Watercraft Warehouse had average receivables of $80,000 and $400,000 of credit sales in a year: 80,000 ÷ 400,000 × 365 = 73 days.

### How is DSO related to receivables turnover?

DSO is the days in the period divided by the receivables turnover. A turnover of 5 in a 365-day year is a DSO of 73 days. OpenStax calls the yearly figure the number of days' sales in receivables.

### Can I work out DSO for a quarter or a month?

Yes. Enter the credit sales for that quarter or month, the receivables at its start and end, and its number of days. $90,000 of sales in a 90-day quarter with average receivables of $30,000 is a DSO of 30 days.

### What is a good DSO?

Compare DSO with your payment terms. If you give customers 30 days to pay, a DSO near 30 means most pay on time. A DSO that climbs from one period to the next means collections are slowing.

### Should I use average or ending receivables?

The average of the starting and ending balances matches sales made over the whole period. If you only have the ending balance, leave the starting box empty and the calculator uses the ending balance.

## Sources

- OpenStax, Principles of Accounting, Volume 1, 9.3 Determine the Efficiency of Receivables Management Using Financial Ratios: accounts receivable turnover = net credit sales ÷ average accounts receivable, average = (beginning + ending) ÷ 2, number of days' sales in receivables = 365 ÷ turnover, and the Billie's Watercraft Warehouse and Company A examples (73 and 43.14 days). https://openstax.org/books/principles-financial-accounting/pages/9-3-determine-the-efficiency-of-receivables-management-using-financial-ratios (retrieved 2026-10-18)
- OpenStax, Principles of Finance, 6.2 Operating Efficiency Ratios: the same accounts receivable turnover, with net sales in place of credit sales when credit sales are not reported. https://openstax.org/books/principles-finance/pages/6-2-operating-efficiency-ratios (retrieved 2026-10-18)