Warning: Your Working Capital Is Probably Trapped on the Shop Floor
A 50-person machine shop in Ohio booked $9.4 million in revenue last year and ended the year unable to make payroll without a line-of-credit draw. The owner thought he had a sales problem. He had a working capital problem, and most of his money was sitting on the shop floor.
What Is Working Capital in Manufacturing?
Working capital in manufacturing is the cash a shop has tied up in day-to-day operations: raw material on the rack, jobs in process at machines, finished goods waiting to ship, and invoices customers have not paid yet, minus what the shop owes suppliers. The standard working capital formula is current assets minus current liabilities. For a manufacturer, most of that "current assets" line is inventory and accounts receivable, not cash in the bank.
That distinction is where shops get into trouble. The balance sheet says the business is healthy. The checking account says otherwise.
According to the National Association of Manufacturers' 2024 outlook survey, 67% of manufacturers cite working capital as a top financial concern. Siemens Financial Services estimated that US manufacturers have roughly $550 billion tied up in operational working capital across the sector. None of that money is earning a return until something ships and somebody pays.
Why Generic Finance Advice Fails for Manufacturers
Most working capital advice was written for software companies, retailers, or service firms. None of those businesses have $400,000 of bar stock in a rack, a job that has been sitting at the bandsaw for nine days because a fixture broke, or a customer on Net 60 terms who only pays after their inspection team signs off.
Manufacturing has structurally longer cash cycles than almost any other industry. The Hackett Group's 2025 working capital survey found that small US companies (under $300 million in revenue) ran a 120-day CCC in 2024. The top-performing manufacturers still sit around 65 days. Compare that to retail, where top performers convert cash in 19 days, and the gap becomes obvious. A retailer who turns inventory in two weeks has a different problem set than a job shop quoting custom parts six weeks out.
Three structural realities make manufacturing different:
- Raw material has to be bought before the job is sold. Steel, aluminum, electronics. Long-lead items get ordered against forecast or against blanket POs, not against confirmed orders.
- WIP can sit for weeks. A part that touches five operations can spend most of its life in a queue, not on a machine. Every day in queue is a day of trapped cash.
- Customers pay slowly. Manufacturing DSO benchmarks run 45 to 75 days, per CreditPulse's 2025 industry data. Net 30 on the invoice rarely means paid in 30.
Advice that works for an agency ("invoice faster," "tighten subscriptions") does not address any of the three.
The Four Places Working Capital Hides on the Shop Floor
If your bank balance feels tight while sales are growing, the cash is somewhere. It is almost always in one of these four buckets.
1. Raw Material You Bought "Just in Case"
Walk the raw material rack. How much of what is on it has a confirmed job behind it, and how much was bought because the buyer wanted a safety stock or got a price break? APQC benchmarks put inventory carrying cost at 20% to 30% of inventory value per year for manufacturers, factoring in cost of capital, storage, insurance, handling, and obsolescence. A $200,000 raw rack costs roughly $50,000 a year to hold whether it moves or not.
The loss is invisible because it is not a line item. It shows up as a slow drip from operating cash and a fatter rack at year-end.
2. WIP Inventory Stuck Between Operations
WIP inventory is the most expensive inventory you carry. Every job in process has labor, machine time, and material in it, but cannot be invoiced until it ships. Manufacturing days inventory outstanding typically runs 60 to 100+ days. Small-manufacturer averages cluster around 5.3 inventory turns per year, which is roughly 69 days of inventory on the floor at any moment.
When WIP rises and revenue does not, the shop is spending faster than it earns, and the gap is filled by debt or owner contributions. Real-time inventory tracking on the shop floor is the only way most shops can see WIP moving in time to do anything about it. A weekly Excel cycle count will not catch a job stalling.
3. Finished Goods Nobody Ordered
Finished goods are the most painful place to find trapped capital because the work is already paid for. The job ran, labor was burned, material was consumed, and the part is now sitting on a shelf waiting for a release date, a customer pickup, or a problem nobody flagged.
Two common causes: build-to-stock policies that outran demand, and customer holds (engineering changes, quality disputes, blanket-order draw schedules) where the part is finished but not invoiceable. Walk the shipping area. If a pallet has a date older than 30 days on its tag, that is locked-up cash.
4. Accounts Receivable That Quietly Slipped
The fourth bucket is the one most owners do not check often enough. Customers shift terms. A long-time account that paid Net 30 for years starts paying Net 45. Then Net 60. Nobody renegotiates the contract; the pattern drifts on its own.
The DSO Efficiency Ratio is the cleanest way to spot the drift. Divide actual DSO by your stated terms. A ratio of 1.0 to 1.15 is fine. Above 1.50 is a compounding cash flow problem that grows every month. For a $10 million shop on Net 30 terms collecting at an actual DSO of 60 days, that is about $820,000 sitting in AR that should be cash. See the early warning signs of a broken AR turnover for what to look at before the drift becomes structural.
A Composite Example: Bridgepoint Precision
Bridgepoint Precision is a composite based on three real machine shops in the Great Lakes region. 42 employees. $11.2 million in revenue. Job shop and short-run production, mostly aerospace and defense subcontract.
The owner thought the business was healthy. Revenue was up 14% year over year. Quote-to-win was at 31%. Then in February the line of credit hit its ceiling, and the bank asked for a working capital review.
What the review found:
| Bucket | Amount Trapped | Days |
|---|---|---|
| Raw material (long-lead aluminum, copper) | $640,000 | ~90 days of supply |
| WIP (38 active jobs, avg 22 days old) | $510,000 | 22 days average age |
| Finished goods awaiting customer release | $290,000 | 60+ days on average |
| Past-due AR (>30 days past terms) | $480,000 | DSO of 67 vs. Net 30 terms |
| Total operational working capital trapped | $1.92M | (sum) |
The shop's annual operating profit was $1.4 million. There was more cash trapped in operations than the shop made in profit for the year.
Within nine months, by tightening raw reorder points, splitting two stalled jobs into staged invoices, releasing $180,000 of finished goods through proactive customer outreach, and shortening terms with two slow payers, Bridgepoint freed about $740,000 in cash. The line of credit went from 94% drawn to 41% drawn. Nothing about the sales pipeline changed.
How the Four Buckets Connect to Your CCC
The cash conversion cycle is the headline number that ties all four buckets together. The formula is days inventory outstanding plus days sales outstanding minus days payable outstanding. A shop with 80 days of inventory, 60 days of receivables, and 40 days of payables runs a 100-day CCC. Every dollar of growth requires roughly 100 days of self-funding before it comes back as cash.
The Hackett Group reported that US firms' overall CCC improved from 38.3 to 37 days in 2024 across the largest 1,000 public companies, mostly by stretching payables. Small manufacturers do not have that lever; they cannot push terms on a sole-source supplier without breaking the relationship. The realistic levers for a sub-$50M shop are inventory turns and AR discipline.
The inventory turnover ratio is the diagnostic. If the shop turned $4 million in average inventory against $20 million in cost of goods, that is 5 turns, or about 73 days of inventory. Pushing turns from 5 to 6 frees roughly $670,000 of cash on the same revenue base. That is real money and it sits there permanently once it moves.
FAQs
What is the difference between working capital and cash flow in manufacturing?
Working capital is a snapshot of current assets minus current liabilities at a point in time. Cash flow is the movement of money in and out of the business over a period. A shop can show positive working capital on paper while running out of cash, because most of the balance is locked in jobs-in-process and unpaid invoices, not in the bank account. Cash flow tells you whether the business funds itself; working capital tells you how much of the funding is stuck in operations.
How much working capital should a manufacturer hold?
There is no single number, but most healthy small and mid-size manufacturers target a current ratio between 1.5 and 2.5 (current assets divided by current liabilities). The more useful question is how many days of operating cash you can fund without borrowing, given your cash conversion cycle. If your CCC is 100 days, you need to fund 100 days of operating expenses from existing cash and credit. Inventory turns and days sales outstanding are the two diagnostics to watch underneath that number.
Can ERP software actually reduce working capital?
A manufacturing ERP reduces working capital when it makes WIP visible in real time, automates reorder points against actual consumption (not forecast), and shortens the invoice-to-cash cycle by linking shipping to billing. The savings come from inventory turns improvement and faster AR, not from the software itself. Most shops that move from spreadsheets to integrated ERP see WIP drop 15% to 25% within a year because nobody has to wait until end-of-month to see where jobs actually are.
See What Is Trapped in Your Operations
Working capital problems are operations problems with a finance label on them. You cannot fix them from the back office because the cash is on the shop floor.
WorkCell ties raw material, WIP, finished goods, and AR into one view so owners can see where the cash actually sits. See how WorkCell's inventory module gives you real-time visibility into the four buckets above, or compare it against your current ERP if you want a side-by-side.