Days Sales Outstanding (DSO)

Days sales outstanding (DSO) is a working-capital metric that shows the average number of days a company takes to turn a credit sale into cash. It compares the money customers still owe, recorded as accounts receivable, with the sales made on credit over a period. Finance teams, lenders, credit analysts and investors use it to judge how well a business collects what it is owed.

DSO is one of three "days" measures that together make up the cash conversion cycle. Its partners are days inventory outstanding, which tracks how long stock sits before it is sold, and days payable outstanding, which tracks how long the company itself takes to pay suppliers. A rising DSO ties up cash in working capital and can be an early sign of weak customers or loose credit control.

Picture a plumber who sends an invoice after every job instead of taking payment on the spot. Some customers pay the same week, others take a month, a few need several reminders. DSO is simply the answer to the question: on average, how long does the plumber wait between finishing the work and seeing the money in the bank?

The shorter the wait, the less the plumber has to borrow to buy parts and pay wages while waiting. If the wait creeps up from three weeks to two months, the business can look profitable on paper while running short of cash. That is why owners and banks watch the number closely, and why a sudden change usually prompts questions about which customers are paying late.

The most common calculation is:

• $\text{Accounts receivable}$ is the balance customers owe at the end of the period (or the average of the opening and closing balances).
• $\text{Credit sales}$ is revenue invoiced on credit during the same period. Where credit sales are not reported separately, analysts use total revenue.
• $\text{Number of days}$ is the length of the period: 365 for a year, about 91 for a quarter, 30 for a month.

Suppose a wholesaler ends the year with receivables of 2.4 million and made credit sales of 14.6 million. DSO is 2.4 divided by 14.6, which is about 0.164, multiplied by 365, giving 60 days. If the wholesaler offers 45-day payment terms, customers are paying on average about two weeks late.

Some companies prefer a "countback" method, which works backwards through recent monthly sales until the receivables balance is used up. It responds better to seasonal businesses, where a strong final month can make the simple formula look worse than reality.

• Agreed payment terms. A firm selling on 90-day terms will naturally show a higher DSO than one selling on 30-day terms, so the number must be read against the terms offered.
• Customer mix. Large retailers, governments and multinational buyers often pay slowly, while small customers may pay quickly or not at all.
• Invoicing and collections. Late or wrong invoices, disputed deliveries and slow follow-up all add days. Good cash application, which matches incoming payments to open invoices, stops paid invoices from appearing as overdue.
• Collection channels. Tools such as lockbox banking, direct debit and electronic payment links shorten the time between a customer paying and the money being credited.
• Customer credit quality. Weak buyers stretch payments when their own cash is tight, which is why DSO often rises ahead of bad debts.

Treasurers use DSO to forecast cash and to size borrowing needs. Each day of DSO represents roughly one day of sales held as receivables, so a company with 14.6 million in annual sales frees about 40,000 of cash for every day it removes from DSO. That makes DSO a common target in working-capital optimization programmes.

Companies that cannot collect faster can still turn receivables into cash early. They can sell invoices through factoring, borrow against them, or sell them under a receivables purchase agreement. In supplier-led programmes such as reverse factoring, the buyer's bank pays the supplier early, which lowers the supplier's DSO without changing the buyer's terms. Lenders that provide a revolving credit facility secured on receivables often exclude invoices that are more than a set number of days overdue, so a rising DSO can directly cut borrowing capacity.

There is no universal "good" DSO. Supermarkets and restaurants, which are paid mostly in cash or by card, can show single-digit figures, while engineering, construction and business-to-business software firms commonly run at 45 to 90 days. The most useful comparisons are against the company's own trend, its stated terms and close peers.

The metric has known weaknesses:

• It is an average. A healthy DSO can hide a small number of very old, possibly uncollectable invoices. An aged receivables report shows the detail.
• It is sensitive to timing. Using a single period-end balance means a large sale on the last day inflates DSO.
• Revenue may include cash sales. Using total revenue in place of credit sales understates DSO for businesses with a high share of cash sales.
• It can be managed. Offering early-payment discounts, selling receivables or chasing collections only near the reporting date can flatter the figure, so analysts read it alongside the statement of cash flows.

• IFRS Foundation
• Financial Accounting Standards Board (FASB)