WIP Calculator: How Much Cash and Lead Time Is Sitting on Your Shop Floor?
Enter a few numbers from your shop. The calculator shows how long a job spends in your shop on average, how much cash your work-in-progress ties up, and what you'd gain by cutting it. Everything runs in your browser: nothing you type is sent or saved.
Your results
Fill in the open jobs, job value and weekly output with numbers above zero (working days 1 to 7, reduction 0 to 90%).
Average lead time (time a job spends in your shop)
Cash sitting on your floor
Cost of that money alone
With % less WIP ( open jobs), same output:
- Average lead time
- Cash freed
- Money cost saved
Opens WhatsApp with your results typed in. Nothing is sent unless you press send.
How the calculator works
Average lead time uses Little's Law, a basic rule of any production system: average lead time = work in progress ÷ output. With 60 open jobs and 15 jobs shipped a week, an average job spends 4 weeks in the shop. At 6 working days a week, that's 24 working days.
Cash on the floor is open jobs × average value per job. Cost of that money is the cash × your yearly cost of money.
The reduction assumes the shop keeps the same weekly output with fewer jobs on the floor, which is what usually happens: extra WIP mostly waits in queues rather than adding output. Lead time and cash fall in the same proportion.
What it leaves out: it's an average, so individual jobs will be faster or slower. And it counts only the cost of money. The real cost of WIP also includes floor space, handling, damage and rework, parts made for orders that change, and the expediting that long queues cause. So treat the money figures as the minimum.
For the full method, including the accounting formula for WIP and how to count it on the floor, read How to Calculate WIP in a CNC Job Shop. To understand why WIP grows in the first place, read Why Your WIP Keeps Increasing.