Many SME owners look at their profit and loss account and see a comfortable profit, yet the bank balance tells a different story. Suppliers get paid late, the overdraft creeps up, and a growing order book somehow makes cash feel tighter rather than looser. The reason is almost never a lack of profitability – it is working capital tied up in stock, unpaid customer invoices and supplier terms that do not match how quickly the business turns raw materials into cash. The cash conversion cycle (CCC) is the single measure that explains this gap, and once you can calculate it, you can start systematically freeing up cash without borrowing a penny more or selling a single extra unit.
What the cash conversion cycle actually measures
The cash conversion cycle answers one practical question: how many days does it take from the moment you pay cash out for stock, to the moment you collect cash in from your customer? It is expressed in days, and it is built from three components that most finance teams already track separately without joining the dots: how long stock sits before it is sold (days inventory outstanding), how long customers take to pay after being invoiced (days sales outstanding), and how long you take to pay your own suppliers (days payables outstanding). Put together, they tell you exactly where cash is trapped in the operating cycle – and by how much.
Breaking it down: DIO, DSO and DPO
- Days Inventory Outstanding (DIO): the average number of days stock sits in the warehouse or on the shop floor before it is sold. Calculated as average inventory divided by cost of goods sold, multiplied by 365.
- Days Sales Outstanding (DSO): the average number of days it takes customers to pay their invoices. Calculated as average trade receivables divided by revenue, multiplied by 365.
- Days Payables Outstanding (DPO): the average number of days you take to pay your suppliers. Calculated as average trade payables divided by cost of goods sold, multiplied by 365.
- Cash Conversion Cycle (CCC): DIO plus DSO minus DPO. The lower this number, the less cash is locked up in day-to-day operations.
Worked example: Brightwood Furniture Ltd
Brightwood Furniture Ltd is a mid-sized bespoke furniture maker turning over £2.4 million a year. Its finance manager wants to understand why the business is increasingly reliant on its overdraft despite steady sales growth. Here are the figures for the most recent financial year.
| Metric | Annual Figure (£) |
|---|---|
| Revenue | 2,400,000 |
| Cost of goods sold (COGS) | 1,560,000 |
| Average inventory | 260,000 |
| Average trade receivables | 330,000 |
| Average trade payables | 210,000 |
| DIO = (260,000 / 1,560,000) x 365 | 60.8 days |
| DSO = (330,000 / 2,400,000) x 365 | 50.2 days |
| DPO = (210,000 / 1,560,000) x 365 | 49.1 days |
| Cash Conversion Cycle = DIO + DSO – DPO | 61.9 days |
This means Brightwood’s cash is tied up in the operating cycle for almost 62 days before it comes back into the bank. Stock sits for over two months before it sells, customers take roughly seven weeks to pay, and Brightwood only holds onto its own cash for around seven weeks before paying suppliers. Every one of those 62 days has to be funded from somewhere – usually the overdraft.
How the transactions behind the numbers actually look
The DIO, DSO and DPO figures are not abstract ratios – they are built from real bookkeeping entries happening every week. Two examples show how individual transactions either lengthen or shorten the cycle.
| Account | Dr | Cr |
|---|---|---|
| Inventory | 45,000 | |
| Trade payables | 45,000 |
Raw materials purchased on 60-day credit terms – this increases average payables and therefore DPO, delaying cash leaving the business.
| Account | Dr | Cr |
|---|---|---|
| Bank | 50,000 | |
| Trade receivables | 50,000 |
Cash collected from a customer following a credit control call chasing an overdue invoice – this reduces average receivables and therefore DSO, bringing cash back into the business sooner.
If Brightwood reduced its days sales outstanding by just 10 days through tighter credit control, it would free up roughly £65,753 in cash (10 divided by 365, multiplied by £2.4 million revenue). A 10-day reduction achieved instead through faster stock turnover would release roughly £42,740 (10 divided by 365, multiplied by £1.56 million cost of goods sold). Either measure would free up substantial cash to clear an overdraft or fund a new hire without external borrowing.
Do not chase a lower CCC by simply delaying supplier payments beyond agreed terms. Stretching DPO artificially can breach agreed terms, count towards reportable late payment statistics for larger businesses, damage supplier relationships, and result in the loss of early settlement discounts or tighter credit terms being imposed in return – often costing more than the cash benefit gained.
Turning the numbers into cash: practical actions
Once you know your CCC and its three components, the improvement actions are usually straightforward and do not require new accounting standards or systems – just discipline in how stock, customers and suppliers are managed.
- Recalculate DIO, DSO and DPO every month using consistent average balances so you can track trends, not just year-end snapshots, and spot problems before they hit the bank balance.
- Tackle DSO first, because it is usually the fastest win: tighten credit terms for new customers, automate payment reminders, and review any invoices over 60 days old at least weekly.
- Review slow-moving stock lines that inflate DIO – clearing aged inventory, even at a discount, releases cash faster than letting it sit waiting for a sale that may never come.
- Negotiate supplier payment terms formally rather than paying late informally, so DPO improvements are sustainable and do not damage supplier goodwill or your own credit standing.
Want a clear view of where your cash is trapped?
We help SME owners and finance teams calculate their cash conversion cycle, benchmark it against industry norms, and build a practical plan to release working capital without new borrowing.
