Days sales outstanding (DSO) is the average number of days a company takes to collect cash after a sale. It is usually calculated as trade receivables divided by revenue for a period, multiplied by the number of days in that period. A rising DSO means cash is coming in more slowly.
What is days sales outstanding?
DSO turns the receivables balance into days of sales. A DSO of 60 means the company has about two months of sales still to collect. It is one of the three parts of the cash conversion cycle, with days inventory outstanding and days payable outstanding, and a core measure of working capital.
No accounting standard defines DSO, so companies calculate it in slightly different ways. What matters is using the same formula every month and saying what it is.
How do you calculate DSO?
| Choice | Common approach | Why it matters |
|---|---|---|
| Formula | Trade receivables ÷ revenue for the period × days in the period | The basic calculation |
| Period | The last 3 months (about 90 days) or the last 12 months (365 days) | A short window reacts faster; a long one is steadier |
| Receivables | The closing balance, or the average of opening and closing | An average smooths one-off swings |
| Revenue | Credit sales only, where cash sales are material | Cash sales lower DSO without any change in collection |
| VAT | Remove VAT from receivables, or add it to revenue | Receivables include VAT; revenue does not |
What does a DSO calculation look like?
Why does DSO matter for GCC finance teams?
Each day of DSO is a day of sales funded by the business instead of the customer. With revenue of SAR 50,000 a day, cutting DSO by 10 days frees about SAR 500,000 of cash, which the 13-week cash flow forecast shows arriving.
In Saudi Arabia, standard-rated sales carry VAT at 15%, so receivables include VAT that revenue does not. Decide whether to remove it and state the choice, especially when comparing companies in different countries with different VAT rates.
Read DSO beside the aging report. An average can look healthy while one large customer is far past due, and a fall in revenue raises DSO even when customers pay on the same days as before.
Questions people ask
What is a good DSO?
It depends on your payment terms and your sector. Compare DSO with your standard terms: if you sell on 30 days and DSO is 55, customers are paying late on average. The trend matters more than any single month.
What is the difference between DSO and DPO?
DSO measures how long customers take to pay you. DPO, days payable outstanding, measures how long you take to pay suppliers, usually payables divided by purchases or costs. The cash conversion cycle is DSO plus days inventory outstanding minus DPO.
Why did DSO rise when collections did not change?
A fall in revenue raises DSO even if the same customers pay on the same days, and so does a large sale near the period end. Check the aging before concluding that collection has slowed.
Official and primary sources, read on the date shown. Rules change: confirm with the authority or your adviser before you act.
- ZATCA news: VAT at 15% in force from 1 July 2020 (read 9 October 2026)