In the first depreciation year the asset is in service, six months' value will be depreciated. Depreciation will begin immediately after the asset is put in service.

Example: The current depreciation year is January through December

Asset 1 is put in service on 10/1 and monthly depreciation is $200. With half-year convention, $1200 (6 months x $200) depreciation must be taken. There are only 3 depreciation periods left in the year, so $400 ($1200/3) will be depreciated each period.

Asset 2 is put in service on 5/1 and monthly depreciation is $200. With half-year convention, $1200 (6 months x $200) depreciation must be taken. There are 8 depreciation periods left in the year, so $150 ($1200/8) will be depreciated each period.