What it means
Net working capital is what remains after subtracting short term obligations from short term assets, and it represents the cash a business has committed to keeping the trading cycle turning. Dividing sales by that figure shows how efficiently that commitment is being used.
Unlike ratios that only look at assets, this one recognises that supplier credit funds part of the cycle for free. The reason finance directors watch it closely is that working capital grows with sales.
If a business needs one dollar of working capital for every eight dollars of sales, then adding $8,000,000 of sales will absorb roughly $1,000,000 of cash before a single dollar of extra profit is banked. Fast growing companies fail for exactly this reason far more often than they fail from poor margins.
A high ratio signals efficient use of working capital, but taken too far it becomes a warning. A business that is stretching supplier payments and running minimal stock to keep the ratio high has no slack, and one bad month can turn an efficiency story into a liquidity problem.
The measure breaks down at the extremes. If current liabilities exceed current assets, net working capital is negative and the ratio becomes meaningless as a percentage of efficiency, although negative working capital is entirely normal for supermarkets and subscription businesses that collect before they pay.
In practice the most valuable use is forward looking rather than historical. Once you know the ratio, you can estimate how much additional cash a growth plan will consume and arrange the funding before the growth starts rather than after the overdraft is refused.
In practice
Real-world examples.
Example
A commercial furniture supplier planning to double sales calculates that its ratio of 6.0 means the extra $5,000,000 of revenue will absorb roughly $833,000 of working capital. It arranges an invoice finance facility before taking the orders rather than after.
Example
An online grocery business operates with negative net working capital because customers pay at checkout while suppliers are paid in 45 days. The ratio cannot be calculated meaningfully, so the board tracks the cash conversion cycle instead.
Example
A machine tool distributor sees its ratio climb from 5.0 to 9.0 in a year and treats it as good news until it notices supplier payments have stretched from 40 to 75 days. Two key suppliers have quietly reduced its credit limit, so the improvement is fragile rather than real.
Think of it
“Sales to working capital shows how hard your working capital cushion works to support sales.
Formula
Calculation
Net working capital = current assets - current liabilities
Sales to net working capital ratio = annual net sales / net working capital
An electrical wholesaler records net sales of $20,000,000. Its current assets are $6,500,000 and its current liabilities are $4,000,000, so net working capital is $6,500,000 - $4,000,000 = $2,500,000.
Sales to net working capital ratio = $20,000,000 / $2,500,000 = 8.0.
Now use it to plan. If sales are expected to grow 25% to $25,000,000 and the business keeps operating at a ratio of 8.0, required working capital becomes $25,000,000 / 8 = $3,125,000, an increase of $3,125,000 - $2,500,000 = $625,000 that must be funded from profit, borrowing or better terms before the growth can be delivered.Case study
Seen in the real world.
The following is an illustrative and fictional example. Pinecrest Fasteners, an invented industrial supplier, was operating at $20,000,000 of sales with $2,500,000 of net working capital, a ratio of 8.0, when it won a national contract expected to add $10,000,000 of annual revenue.
The finance director ran the arithmetic before the contract was signed. At the same ratio, $30,000,000 of sales would need $3,750,000 of net working capital, meaning $1,250,000 of extra cash absorbed by stock and customer credit within the first year, largely before the new customer paid anything at all.
In this fictional case Pinecrest negotiated 45 day payment terms with the new customer instead of the 60 days first proposed, and agreed a $750,000 seasonal overdraft. The contract was delivered without a cash crisis, and the board adopted a rule that no contract above $1,000,000 could be signed without a working capital calculation attached.
Watch out
Common mistakes.
- Assuming a higher ratio is always better, when it can mean the business has almost no cushion against a late payment or a slow month.
- Calculating the ratio when net working capital is negative and then trying to interpret the result as an efficiency measure.
- Planning a growth target without translating it into the additional working capital that growth will consume.
Questions
People also ask.
What is a reasonable ratio to aim for?
It depends heavily on the sector, so most businesses set a target based on their own three year history and their nearest competitors rather than a general rule.
Does this ratio replace the current ratio?
No, the current ratio tests whether short term debts can be met, while this one tests how much trading each dollar of working capital supports.
Should overdrafts be included in current liabilities?
Yes, a repayable on demand overdraft is a current liability, which is one reason a business relying heavily on one can show a deceptively high ratio.
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