Working Capital Explained: How to Calculate and Improve It
Working capital is the money tied up in running your business day to day: the cash waiting in unpaid invoices, sitting on shelves as stock, or owed to suppliers. Understand it and you can often free up thousands of dollars without selling anything extra. This explainer covers the formula, the cash conversion cycle and the levers that improve both.
Key takeaways
- Working capital = current assets − current liabilities. Positive means you can cover near-term obligations; negative means you need new cash or credit.
- The cash conversion cycle measures how many days cash is tied up between paying suppliers and collecting from customers.
- Growth consumes working capital. A business can be profitable and still run out of cash because sales are rising.
- The fastest improvements come from collecting sooner, holding less stock and negotiating supplier terms.
Imagine a profitable business that wins a big new customer, doubles its orders and goes bankrupt six months later. It happens more often than most people think, and the cause is almost always working capital. The business had to pay for materials and wages weeks before the customer paid, and it did not have enough cash to bridge the gap.
Working capital is the finance concept that explains that gap. It is less famous than profit, but for a growing small business it is often more important.
The formula
Working capital = current assets − current liabilities
Current assets are things that are cash or will become cash within a year: the bank balance, accounts receivable (what customers owe you), inventory and prepaid expenses. Current liabilities are what you must pay within a year: accounts payable (what you owe suppliers), credit card balances, short-term loans, the next twelve months of a long-term loan, accrued wages and taxes due.
Both figures come straight from your balance sheet.
Worked example
Suppose a small furniture maker has $25,000 in the bank, $60,000 in unpaid customer invoices and $45,000 of inventory, for current assets of $130,000. It owes $38,000 to suppliers, has a $12,000 credit card balance and $20,000 of loan payments due in the next year, for current liabilities of $70,000. Working capital is $130,000 minus $70,000, which is $60,000. That is the cushion between what is coming in and what is going out over the next year.
The current ratio
Dividing current assets by current liabilities gives the current ratio, which makes businesses of different sizes comparable. The furniture maker's ratio is $130,000 ÷ $70,000, about 1.86. Below 1.0 means current liabilities exceed current assets. Many lenders like to see 1.2 to 2.0, though it varies widely by industry. A ratio far above 2.0 can mean cash or stock is sitting idle.
The quick ratio is stricter: it leaves out inventory, because stock may take months to turn into cash. For the furniture maker, that is $85,000 ÷ $70,000, about 1.21.
Common mistake
Assuming a healthy current ratio means healthy cash. A business can have a ratio of 2.0 and no money in the bank if its current assets are mostly slow-paying receivables and unsold stock. Always look at the components, not just the total.
The cash conversion cycle: working capital in days
The balance sheet shows working capital at one moment. The cash conversion cycle (CCC) shows how long it takes to turn money spent on inventory back into money collected from customers. It combines three measures:
- Days inventory outstanding (DIO): average inventory ÷ cost of goods sold per day. How long stock sits before it sells.
- Days sales outstanding (DSO): accounts receivable ÷ sales per day. How long customers take to pay.
- Days payable outstanding (DPO): accounts payable ÷ cost of goods sold per day. How long you take to pay suppliers.
CCC = DIO + DSO − DPO
Worked example
Continuing with the furniture maker. Annual sales are $720,000, so sales per day are about $1,973. Annual cost of goods sold is $432,000, about $1,184 a day. DIO is $45,000 ÷ $1,184, roughly 38 days. DSO is $60,000 ÷ $1,973, about 30 days. DPO is $38,000 ÷ $1,184, about 32 days. The cash conversion cycle is 38 + 30 − 32, which is 36 days. On average, every dollar the business spends on materials is tied up for 36 days before it comes back as cash from a customer.
What the number means in dollars
Multiply the cycle by daily cost of goods sold to see roughly how much cash the cycle absorbs: 36 days × $1,184 is about $42,600. Cut the cycle to 26 days and you free up about $11,800 of cash permanently, with no change in sales or profit. That is the practical power of managing working capital.
Why growth eats cash
Here is the trap that catches profitable businesses. Suppose the furniture maker lands a contract that doubles sales. Inventory, receivables and payables all roughly double with it. Working capital tied up in the cycle goes from about $42,600 to about $85,000. The business must find around $42,000 of extra cash to fund the growth before the new profits arrive. If it does not have that cash or a credit line, it will run short while its order book is the fullest it has ever been.
The rule of thumb: for every dollar of additional annual sales, you need roughly (CCC ÷ 365) × cost of goods per dollar of sales in extra working capital. For a 36-day cycle and 60% cost of goods, that is about 6 cents per dollar of new sales. A $300,000 sales increase needs about $18,000 of cash up front.
Seven ways to improve working capital
- Invoice immediately. Every day between finishing work and sending the invoice is a day added to DSO. Invoice on delivery, not at month end.
- Shorten payment terms and ask for deposits. Move from 30 days to 14 where the market allows, and take a 30% to 50% deposit on custom or large orders. Rules on late payment interest and permitted terms differ by country; in the US they are mostly set by contract, while the UK and EU have statutory late-payment rules, so check what applies to you.
- Chase systematically. A reminder two days before the due date, another on the day and a phone call a week later cut DSO more than any software. Offer a small early-payment discount only if the math works: 2% for paying 20 days early works out to roughly 37% a year, which is expensive money.
- Hold less stock. Rank products by sales velocity, cut reorder quantities on slow lines, clear dead stock at a discount and negotiate smaller, more frequent deliveries.
- Negotiate supplier terms. Ask for 45 or 60 days instead of 30 once you have a payment record. Pay on the due date, not early, unless a discount makes early payment worthwhile.
- Use the right financing for the gap. A revolving line of credit or invoice financing is designed for working capital. A long-term loan or a merchant cash advance usually is not.
- Review the cycle quarterly. Calculate DIO, DSO and DPO every quarter and set a target for each. A one-day improvement across all three on $720,000 of sales frees roughly $3,500.
Working capital by business type
| Business type | Typical pressure | Biggest lever |
|---|---|---|
| Retail | Cash tied in inventory, customers pay instantly | Stock turnover and supplier terms |
| B2B services | Long receivables, little stock | Invoicing speed, deposits, collections |
| Manufacturing | Raw materials, work in progress and receivables all at once | Production scheduling, deposits, supplier terms |
| Subscription software | Often negative cycle if billed annually in advance | Annual billing, upfront payment incentives |
| Restaurants and cafés | Low receivables, perishable stock, supplier credit | Purchasing discipline and waste control |
Pro tip
Put DSO on your monthly dashboard next to sales. When sales grow and DSO grows with them, you are financing your customers' growth with your own cash, and the bank balance will tell you so a few weeks later.
Signs working capital is healthy
- Current ratio between about 1.2 and 2.0 for your industry
- Cash conversion cycle stable or falling
- DSO close to stated payment terms
- Growth funded from operating cash flow
Warning signs
- Rising receivables while sales are flat
- Inventory growing faster than sales
- Paying suppliers late to cover payroll
- Using long-term debt or card balances to fund daily operations
Your working capital checklist
- Pull current assets and current liabilities from your latest balance sheet and calculate working capital and the current ratio
- Calculate DIO, DSO and DPO from the last twelve months and add them up to get your cash conversion cycle
- Convert the cycle into dollars: cycle days × daily cost of goods sold
- Set a target to cut the cycle by ten days over the next two quarters
- Fix invoicing timing, add deposits and build a three-step reminder sequence
- Rank inventory by velocity and clear slow stock
- Arrange a line of credit before you need it, not during a crunch
Frequently asked questions
Is negative working capital always bad?
No. Businesses that collect from customers before paying suppliers, such as many retailers, restaurants and subscription companies, can run negative working capital safely because cash keeps arriving. It becomes dangerous when it is caused by slow collections or overdue bills rather than by a fast cycle.
How much working capital does a small business need?
Enough to cover the cash conversion cycle plus a buffer for surprises. A practical minimum for many small businesses is cash equal to one to three months of fixed costs, on top of what the cycle absorbs. Lenders and advisers can help set a figure for your industry.
What is the difference between working capital and cash flow?
Working capital is a balance at a point in time. Cash flow is movement over a period. Changes in working capital are one of the main reasons cash flow differs from profit: if receivables rise by $10,000, that is $10,000 of profit you have not yet collected.
Should I use a working capital loan?
A revolving line of credit sized to your cycle is a normal tool for seasonal or growing businesses. Borrowing to cover a permanent shortfall caused by poor collections or excess stock only delays the problem. Fix the cycle first, then borrow to fund growth.
Related reading
The bottom line
Working capital is current assets minus current liabilities, and the cash conversion cycle is that same idea measured in days. Calculate both, turn the cycle into dollars and you will see exactly how much cash your operations absorb. Then invoice faster, collect sooner, hold less stock and negotiate terms. For most small businesses, that is the cheapest money they will ever find.
