How to track and control WIP in a garment factory
To control WIP (work in progress) in a garment factory, record every move of pieces between departments, count WIP by department, component, size and colour, and compare it with daily output to see where work is piling up. WIP is everything that has started but is not yet a finished garment: cut panels, printed parts, stitched bodies and pieces waiting for finishing.
This guide is for production managers. It shows where WIP builds up, how to measure it, a simple way to see bottlenecks, and the habits that keep pieces from getting lost between floors. For how Karpan ERP records production, see garment production and WIP tracking.
Where WIP builds up
- Cut store: cut panels waiting for sewing, often sorted by size but not by line.
- Before sewing lines: bundles issued but not yet started.
- Between sewing and finishing: stitched garments waiting for thread cutting, checking, ironing and packing.
- At outside processors: panels at the printer, embroiderer or washer.
- Alteration and rejects: pieces waiting for rework, often forgotten until the shipment is short.
Why too much WIP hurts
- It ties up cash: fabric and labour already spent on pieces that cannot be shipped.
- It hides problems: a slow line or a missing component is not visible under a pile of bundles.
- It gets mixed: sizes, colours and lots end up in the wrong place.
- It gets lost: the more pieces sit between floors, the more go missing.
How to measure WIP
For each department, WIP is simple arithmetic:
WIP = pieces received into the department − pieces sent out − pieces rejected
If stitching received 1,200 cut sets, sent 980 stitched bodies to finishing and rejected 20, its WIP is 1,200 − 980 − 20 = 200 pieces.
Count it by component, size and colour, not only as a total. 200 pieces of WIP is fine if they are evenly spread; it is a problem if all 200 are size XL in one colour that the buyer needs first.
Spot the bottleneck: WIP in days
Divide each department’s WIP by its daily output. The result is how many days of work are waiting there.
| Department | WIP (pieces) | Daily output | WIP in days |
|---|---|---|---|
| Stitching | 200 | 400 | 0.5 |
| Finishing | 3,000 | 600 | 5 |
In this example, finishing is the bottleneck: work is piling up there, not in stitching. Moving people or overtime to finishing will ship orders sooner than pushing stitching harder. (Sample numbers.)
Match components, not just pieces
A shirt needs a front, a back and a pair of sleeves. If stitching holds 240 fronts, 236 backs and 230 pairs of sleeves in size M, it can make only 230 shirts in that size. Counting 706 “pieces” of WIP hides the fact that sleeves are short. Track WIP by component, and the shortage shows up before the line stops.
Habits that keep WIP under control
- Work order first. Every department or outside unit works against a work order for an order and style.
- Document every move. No transfer between departments without an issue or transfer record.
- Receive by size and colour. Not just a total count.
- Keep alteration and rejects separate. Give them their own stock and follow them until they are fixed or written off.
- Review WIP daily. Look at WIP in days by department each morning.
- Set limits. Decide how much WIP each department should hold, based on its daily output, and stop issuing more when it is reached.
Common mistakes
- Counting only finished garments and treating everything else as “on the floor”.
- Pieces moving between floors on verbal instructions.
- Forgetting panels lying at the printer or embroiderer.
- Mixing alteration pieces back into good stock without a record.
How Karpan ERP tracks WIP
In Karpan ERP, work orders are approved before material moves. Material is issued to departments or outside suppliers against the work order, component WIP moves from department to department, and the WIP stock screen shows what each department holds by component, size and colour. Assembly works out the most garments a department can make from the components it holds. Output is received by size and colour, and alteration and reject stock is kept separate. Karpan tracks production by document, not by bundle or operator. See production and WIP in Karpan ERP.
Questions people ask
How do you calculate WIP in a garment factory?
For each department, WIP = pieces received − pieces sent out − pieces rejected. Count it by component, size and colour.
How do you find the bottleneck in garment production?
Divide each department’s WIP by its daily output to get WIP in days. The department with the most days of work waiting is usually the bottleneck.
How much WIP should a garment factory hold?
Enough to keep the next department working without gaps, and not much more. Set a limit for each department based on its daily output and review it as orders change.
How can a garment factory reduce WIP?
Issue work only against work orders, record every transfer, fix the bottleneck department first, match components before issuing to sewing, and clear alteration pieces quickly.