Days sales outstanding: what DSO tells a small business, and how to reduce it

The definition

Days sales outstanding is the average number of days it takes to collect payment after a sale is invoiced. The standard formula is:

DSO = (accounts receivable at the end of the period ÷ revenue invoiced in the period) × days in the period.

An example, with round numbers chosen for the arithmetic: a firm closes the quarter with $450,000 of unpaid invoices, invoiced $900,000 during the quarter, and the quarter had 91 days. Its DSO is 450,000 ÷ 900,000 × 91, which is about 46 days.

Use revenue invoiced on credit, which for a B2B services company is almost all of it. Use the same period length every time, and calculate it on the same day of the month, so that the trend is comparing like with like.

Reading the number against your own terms

DSO means little on its own. It means a great deal next to your payment terms. A firm on thirty-day terms with a DSO of 46 is being paid sixteen days late on average. A firm on sixty-day terms with the same DSO is being paid early.

The second reading is the trend. A DSO that climbs a few days each quarter is a slow change in how your clients treat you, and it costs the same as if you had extended everyone’s terms without being asked. Watch the direction before you worry about the level.

What the average hides

DSO is an average, and in a company with a small number of large clients, an average conceals the client that matters. Ten clients paying in thirty days and one large client paying in ninety can produce a DSO that looks acceptable while the large client’s invoices quietly fund a third of your payroll.

So read DSO beside the aged receivables list, which shows each unpaid invoice by how long it has been outstanding. And track one more figure DSO does not include: the days from work done to invoice sent. Work that has been delivered but not yet invoiced is not a receivable, so it is invisible to DSO, but it is cash you have not started collecting. A team that invoices a week after month-end has added a week to every client’s payment time before the client has done anything.

A late payer is a cash problem before it is a sales problem

Inside the business, a late-paying client looks fine to almost everyone. The account manager has a happy client. The delivery team has a running project. The revenue is in the P&L the day the invoice is raised.

The cost sits in one place only: the bank. Take a project billed monthly to a client who pays in seventy-five days. By the time the first invoice is paid, you have run three monthly payrolls for that team. You are lending that client your payroll, without interest and without having agreed to it.

This is why DSO belongs in the owner’s weekly view and not only in the bookkeeper’s. The commercial decision, how much work to take from a client who pays this way and on what terms, is the owner’s, and it can only be taken if the cost is visible.

Which receivables to chase first

Chasing every overdue invoice in date order is the usual approach, and it spends effort where it moves the least cash. Order the list by what each invoice does to the next few weeks instead.

• First, the invoices your cash forecast relies on in the next four weeks, especially any that fall before a payroll date
• Next, the largest overdue amounts, judged against how late that client usually is: a client who always pays at forty days is not a problem at day thirty-five; one who usually pays at thirty is
• Then the disputed or stuck invoices, where the fix is usually administrative: a missing purchase order number, an unsigned timesheet, the wrong contact in accounts payable
• Small old invoices last, and decide once whether to keep chasing or write them off

How to bring DSO down

Most of what lowers DSO happens before the invoice is overdue, and very little of it requires a hard conversation.

Invoice on the day the work is accepted, not at the end of the month. Put the client’s purchase order number, the right billing contact and the agreed scope on the invoice the first time, since an invoice that bounces back for a correction restarts the client’s payment clock. Agree milestone or monthly billing on long projects rather than one invoice at the end, and take a deposit on new work from a new client.

Send a short reminder a few days before the due date, not after it. Agree a fixed escalation: who calls the client and on which day overdue, so that chasing is a routine and not a decision someone has to make each time. And for a client who stays slow, take it to the owner: the next statement of work is the moment to change their terms.

Payment terms are part of the price

Sixty-day terms on a project are a loan to the client for the difference between sixty days and the day you pay your team. That loan has a cost, and the cost can be calculated.

Cost of terms = invoice amount × your annual cost of money × extra days ÷ 365.

Your cost of money is the rate on your overdraft or credit line, or, if you hold cash, what that cash would otherwise earn. Run the formula for a large client on long terms and the number is a real line in the deal. Put it there: quote the rate on standard terms, and the same rate with the cost of longer terms added. A client who wants sixty days can have them, at a price that reflects what they cost you.

The point is not to refuse long terms. It is to stop giving them away inside a rate that was calculated as if the client paid on day thirty.

Seeing the effect on your own cash

CeoDash builds its thirteen-week cash forecast on the timing you actually collect on, not on the terms printed on the invoice, so a slow client shows up as the week your balance gets tight rather than as a ratio in a report. Load the files you already have and the first figures show in minutes.