Learn how work-in-progress inventory accumulates materials, labor, and production overhead before completed goods move to finished inventory.
Work in progress (WIP) is inventory that has entered production but is not complete enough to be classified as finished goods. Its carrying amount generally includes direct materials, direct labor, and an appropriate allocation of production overhead incurred to bring the partially completed goods to their current condition.
WIP is sometimes called work in process, especially in manufacturing and process-costing systems. The terms are often interchangeable in practice, but the accounting policy and industry context control.
The physical and accounting flow is:
Raw materials -> Work in progress -> Finished goods -> Cost of goods sold
When materials are issued to production, their cost moves from raw-material inventory into WIP. Direct labor and production overhead are added as conversion occurs. Once units are complete, their accumulated cost moves from WIP to finished goods. The cost becomes cost of goods sold when the related goods are sold.
The period relationship is:
Manufacturing costs added commonly include direct materials used, direct labor, and applied production overhead.
The formula is a reconciliation. It does not prove that quantities exist, costs are appropriate, or the inventory is recoverable.
A manufacturer reports:
| WIP component | Amount |
|---|---|
| Beginning WIP | $120,000 |
| Direct materials added | $460,000 |
| Direct labor added | $300,000 |
| Production overhead applied | $220,000 |
| Cost transferred to finished goods | ($970,000) |
| Ending WIP | $130,000 |
The calculation is:
$120,000 + $460,000 + $300,000 + $220,000 - $970,000 = $130,000
If the physical production report supports only $105,000 of incomplete work, the $25,000 difference needs investigation. Possible causes include unrecorded completions, scrap, inaccurate completion percentages, stale production orders, or excessive overhead application.
Materials become WIP when they are introduced into production and contribute to the incomplete goods. Materials still in storage remain raw-material inventory. Consumable supplies may be direct or indirect depending on traceability and significance.
Labor that can be traced to production is assigned to WIP. Selling, general administrative, training, and idle-time costs do not become direct labor merely because production employees incurred them.
Variable overhead is allocated based on actual use of production facilities. Fixed production overhead is allocated based on normal capacity under U.S. GAAP and IFRS inventory principles. FASB guidance identifies abnormal idle-facility expense, freight, handling, and wasted material as current-period charges.
Overproducing solely to spread fixed overhead across more units can lower reported unit cost while increasing inventory and cash tied up in stock. Analysts should compare production volume with demand, sales, and inventory growth.
| System | How WIP is accumulated | Typical evidence |
|---|---|---|
| Job costing | Costs are accumulated by individual job, batch, or production order | Job tickets, material requisitions, labor records, overhead application |
| Process costing | Costs are accumulated by department or process and spread across equivalent units | Production reports, units started/completed, completion percentages, equivalent-unit schedules |
In process costing, units can be 100% complete for materials but only 40% complete for conversion. Equivalent units convert partially completed production into a common basis for assigning material and conversion costs. The percentage should reflect actual production stage, not a convenient target chosen to reach a desired margin.
| Label | What it usually represents | Why it differs from manufacturing WIP |
|---|---|---|
| Raw materials | Inputs not yet placed into production | No conversion into goods has begun |
| Finished goods | Completed products available for sale | Production is complete |
| Construction in progress | Capital cost of an entity’s own property, plant, or equipment under construction | Usually a long-lived asset, not goods held for sale |
| Contract asset | Conditional right to consideration for performance transferred to a customer | Arises under revenue guidance rather than simply from incomplete physical production |
| Capitalized software cost | Qualifying development cost under applicable internal-use or software-to-be-sold guidance | Recognition depends on software-specific criteria, not ordinary inventory flow |
A homebuilder can hold homes under construction as inventory when they are developed for sale in the ordinary course of business. By contrast, a factory being built for the company’s own use is construction in progress within property, plant, and equipment. The physical phrase “unfinished project” does not decide the accounting classification.
Reliable WIP measurement requires evidence for both quantity and stage of completion. Useful support includes:
Standard costs can support timely reporting, but companies must analyze purchase, labor, usage, yield, and overhead variances. Large unfavorable variances should not remain capitalized without evidence that they represent normal production cost.
WIP is still inventory and must be tested under the applicable subsequent-measurement rules. An entity estimates the selling value of the finished product and subtracts costs still needed to complete and sell it. If expected recovery does not support the accumulated WIP and future conversion costs, a write-down may be required.
Potential warning signs include:
The lower-of-cost model differs by framework and inventory method. See the lower-of-cost-and-NRV rule and lower of cost or market for the distinction.
WIP classification and measurement depend on the production process and reporting framework. This page is educational and is not accounting, audit, tax, or investment advice.