Construction work in progress is a general ledger account, categorized as a fixed asset, in which you record the costs directly associated with constructing an asset.
Once the asset is placed in service, all costs associated with it that are stored in the construction work in progress account are shifted into whichever fixed asset account is most appropriate for the asset. The most common fixed asset account to which these costs are shifted is Buildings, since most construction projects relate to that fixed asset. However, the account is also sometimes used for machinery, and as such would store the costs associated with buying, transporting, installing, and testing machinery.
While costs are being accumulated in the construction work in progress account, you should not commence depreciating an asset, because it has not yet been placed in service. Once the asset is placed in service and shifted to its final fixed asset account, you should begin depreciation. Thus, the construction work in progress is one of only two fixed asset accounts that are not depreciated. The other account that is not depreciated is the land account.
The construction work in progress account is a prime target of auditors, since costs may be stored here longer than they should be, thereby avoiding depreciation until a later period.