Net Working Capital and the Cash Conversion Cycle
Growth ties up cash in receivables and inventory before it ever converts back to cash. Here is how to measure how much, and how long it takes, using DSO, DIO, and DPO.
What is net working capital?
Net working capital is the cash tied up in a business's day-to-day operating cycle: receivables plus inventory, less payables. An increase in net working capital consumes cash and reduces free cash flow; a decrease frees cash up. The cash conversion cycle, DSO plus DIO minus DPO, measures how many days that cash stays tied up before it returns.
Key takeaways
- Operating NWC = accounts receivable + inventory − accounts payable, deliberately excluding cash and short-term debt.
- Cash conversion cycle = DSO + DIO − DPO, expressed in days.
- An increase in NWC is a use of cash and is subtracted in unlevered free cash flow.
- Growth usually widens NWC, which is why fast-growing companies can be profitable and still consume cash.
- A negative cash conversion cycle means suppliers fund the operating cycle, so growth generates cash rather than consuming it.
What is net working capital?
- Net working capital (operating)
- The cash a business has tied up in running its day-to-day operating cycle: accounts receivable plus inventory, net of accounts payable, excluding cash and short-term debt because those are financing rather than operating items.
Net working capital, in the sense finance interviews and models use the term, is the cash tied up in a business's day-to-day operating cycle: mainly accounts receivable and inventory, net of accounts payable. This “operating” NWC deliberately excludes cash itself and short-term debt, which are financing items, not operating ones, unlike the broader accounting definition of working capital (all current assets minus all current liabilities).
The reason it matters: an increase in NWC ties up cash the business would otherwise have, and a decrease frees cash up, exactly the mechanic behind the ΔNWC term in unlevered free cash flow (see the DCF guide) and one of the links between the income statement and cash flow statement (see the cash flow statement guide).
How do you calculate the cash conversion cycle?
The cash conversion cycle (CCC) measures how many days, on average, cash is tied up in the operating cycle before it comes back in. It combines three separate measures, each expressed in days:
Days Inventory Outstanding (DIO) = Inventory ÷ COGS × 365
Days Payable Outstanding (DPO) = Accounts Payable ÷ COGS × 365
Cash Conversion Cycle = DSO + DIO − DPO
DSO measures how long it takes to collect from customers after a sale. DIO measures how long inventory sits before it's sold. DPO measures how long the company takes to pay its own suppliers, which is why it's subtracted: a longer DPO means suppliers are effectively financing more of the operating cycle, reducing how much cash the company itself has to tie up.
Worked example: DSO of 45 days, DIO of 60 days, DPO of 30 days.
| Metric | What it measures | Effect on the cycle |
|---|---|---|
| DSO | Days to collect cash from customers after a sale | Longer DSO lengthens the cycle |
| DIO | Days inventory sits before it is sold | Longer DIO lengthens the cycle |
| DPO | Days the company takes to pay its own suppliers | Longer DPO shortens the cycle |
What does a negative cash conversion cycle mean?
Some businesses, particularly fast-turning retailers and subscription companies, collect cash from customers before they ever have to pay their own suppliers, producing a negative CCC. That means the business is effectively funded by its suppliers' working capital rather than its own, a structurally favorable position that shows up as a source, not a use, of cash as the business grows: growth itself generates cash rather than consuming it.
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Common working capital interview questions
Why exclude cash and short-term debt from the net working capital used in a DCF?
The version of net working capital used in unlevered free cash flow is meant to capture only operating items, the cash tied up in running the business day to day. Cash itself and short-term debt are financing items, not operating ones, and including them would mix financing effects into a cash flow figure that's supposed to be pre-financing.
What does a negative cash conversion cycle mean?
It means a company collects cash from its customers before it has to pay its own suppliers, so its operating cycle is effectively funded by supplier credit rather than the company's own capital. Growth then generates cash rather than consuming it, a favorable structural feature common in fast-turning retail and subscription businesses.
How does an increase in inventory affect free cash flow?
An increase in inventory means cash was spent building up stock that hasn't sold yet, so it increases net working capital and reduces free cash flow by that same amount, the same mechanic covered in the DCF guide's unlevered free cash flow formula.
Why does net working capital tend to become a bigger drag on cash flow for a fast-growing company?
As revenue grows, receivables and inventory typically grow with it, since a bigger business carries more customers owing it money and more product on hand. Unless payables grow just as fast, that means a larger and larger cash outlay is required each period just to fund the bigger operating cycle, even before any profit is considered.
What's the difference between working capital and net working capital?
Working capital in the broad accounting sense is all current assets minus all current liabilities, including cash and short-term debt. The net working capital used in a DCF or cash flow statement context is narrower: just the operating pieces, receivables and inventory net of payables, which is what actually reflects the cash tied up in running the business.