Issue #46

Days Sales Outstanding and the $112,000 wait

Happy Monday,

Welcome back to Balance Sheet. Every issue follows one real business with a problem hiding in its numbers, walks through what went wrong on the books, and shows you the fix.

Today's issue is about days sales outstanding, the number that tells you how long customers take to pay you. Marisol Ortega runs a commercial cleaning company in Raleigh, North Carolina, and $112,000 of her cash was sitting in her customers' bank accounts past the due date. She was drawing on a 9% line of credit to make payroll while her income statement showed a healthy profit. The fix was a days sales outstanding calculation, broken down customer by customer.

Let’s see how it started and what it can teach you before you send your next invoice.

Payroll Fridays

Brightline Facility Services cleans office parks, medical suites, and apartment lobbies across the Triangle. Thirty-one employees, fourteen contracts, and every invoice on net 30 terms.

On paper, 2026 was her best year. Revenue was on pace for $1.46 million, and net income was up 18%.

But every other Friday, the same thing happened. Payroll ran $38,000, the checking account came up short, and Marisol drew on the line of credit to cover the gap. The balance on that line had climbed to $90,000 by September.

"They always pay late" was her explanation, and everyone in the office agreed. Nobody had put a number on it.

Her bookkeeper, Dev Raman, finally did.

The formula

Days sales outstanding (DSO) measures the average number of days between making a credit sale and collecting the cash.

DSO = (Average accounts receivable ÷ Credit sales) × Number of days

Two details matter here.

First, use credit sales only. Cash sales get collected on day zero, and including them makes your DSO look better than it really is.
Second, use average accounts receivable, the beginning balance plus the ending balance divided by two. Your A/R balance moves all year, and a single snapshot can catch it on an unusually good or bad day.

Brightline's numbers for the trailing twelve months:

Line item	Amount
Credit sales	$1,460,000
Beginning A/R	$196,000
Ending A/R	$268,000
Average A/R	$232,000

DSO = ($232,000 ÷ $1,460,000) × 365 = 58 days

Her terms said 30 days. Her customers were taking 58.

Turning days into dollars

A DSO of 58 sounds like a mild annoyance. It gets serious once you convert it into cash.

Daily credit sales = $1,460,000 ÷ 365 = $4,000 Days beyond terms = 58 - 30 = 28 Cash tied up past terms = 28 × $4,000 = $112,000

That's $112,000 of revenue Brightline had already earned, already recognized on the income statement, and already paid wages to produce. Under accrual accounting, it counted as income the day the work was done. It just hadn't arrived in the bank.

And because Marisol borrowed to fill the hole, the late payments carried a price tag.

Annual carrying cost = $112,000 × 9% = $10,080

Her customers were effectively getting a $10,000 interest-free loan from a cleaning company. "They always pay late" finally had a dollar figure attached.

The average was hiding the real problem

Things get interesting from here though. Dev ran the same formula for each customer, and the slow payers turned out to be a very short list.

Customer	Annual billings	Average A/R	DSO
Harborview Property Group	$438,000	$100,800	84 days
Capital Medical Partners	$219,000	$43,200	72 days
Remaining 12 clients	$803,000	$88,000	40 days
Total	$1,460,000	$232,000	58 days

Twelve of fourteen clients paid within about ten days of terms. Two customers, holding 45% of revenue, dragged the whole company to 58.

Harborview was her largest account, and it knew it. Big customers often stretch payments because they have the negotiating leverage to get away with it. Capital Medical's problem was simpler. Its invoices went to a general inbox and sat there until someone noticed them.

Dev found one more issue, and this one was on Brightline's side. Marisol batched her invoices and sent them around the 10th of the following month. A job finished on August 31 didn't get billed until September 10. That added roughly ten days to every customer's DSO before any customer had a chance to be slow.

What changed

The fix took about three weeks to set up. But it kind of looks like this:

Invoices go out on the last business day of the month, the same day the work closes out.
Harborview moved to ACH autopay at its contract renewal, with a 1.5% monthly late fee written into the new terms.
Capital Medical's invoices now go to a named accounts payable contact, with a reminder on day 25.
Any account past 60 days goes on credit hold until it's current.
Dev reviews the A/R aging report every Monday and calculates DSO at each month-end.

By the end of the next quarter, Brightline's DSO was 41 days.

Cash tied up past terms = (41 - 30) × $4,000 = $44,000

That freed $68,000. The line of credit went to zero by December, and payroll Fridays stopped being stressful.

How to read your own DSO

For many small businesses, a DSO under 45 days is a reasonable target, though industry changes the picture a lot. A manufacturer selling expensive equipment to large companies might live at 80 days comfortably. A clothing retailer at 80 days has a serious collections problem.

So compare against businesses like yours, and pay even closer attention to the trend. A DSO creeping from 38 to 44 to 51 over three quarters is an early warning. It can mean customers are struggling, a salesperson is offering longer terms to close deals, or credit is going to customers who shouldn't get it.

Seasonality matters too. If your DSO jumps every December because clients slow down over the holidays, that pattern is normal. Unexplained swings deserve a closer look.

One more caution. Fast sales growth can push DSO down for a while, because credit sales grow faster than receivables catch up. Check whether collections actually improved before you celebrate.

Back to Brightline

Marisol's income statement was accurate all year. Brightline really was profitable. The problem was timing, and timing was costing her real money.

Every dollar sitting in accounts receivable is a dollar the business can't use for payroll, supplies, or growth. Calculate DSO once a month, break it down by customer, and the slow payers will show up long before the line of credit does.

On Friday, the cash conversation goes one level deeper. A business can post rising profits and still produce negative free cash flow, and growing receivables are one of the biggest reasons why. You'll meet a business owner who learned that from an investor, in the middle of a pitch meeting.