Single-Line Method
The single-line method recognizes the same amount of expense to each period of the asset's useful life. The first step in this method is to calculate the cost to be depreciated, found by subtracting the salvage value from the total cost of the asset (NOTE: total cost includes ALL expenses incurred throughout the process of getting the asset ready to be put into use). Next, this cost to be depreciated is divided by the number of accounting periods in the asset's useful life.
For example, if we have purchase a tractor for $5,000 and used for the entirety of its predicted 10 year useful life when it is realized that a salvage value of $200 exists, the depreciation will be calculated as follows:
(5,000-200)/10 = $480/year
Units-of-Production Method
The Units-of-Production Method charges a different amount for each period of the useful life depending on how many units are produced - the asset's usage. There are also two steps to this process as well. The first is to find the depreciation per unit - how much the asset is to be depreciated with each unit of production - which is calculated by dividing the cost to be depreciated (described above) by the expected total units of production at the end of the asset's useful life. Next, this depreciation per unit is to be multiplied by the units produced in the specific period of needed calculation.
Example: (Consider the situation about the tractor above) This tractor is expected to mow 10,000 fields in it's useful life. In its third year, it mows 800 fields. The depreciation for the third year is computed as follows:
(5,000-200) / 10,000 = $0.48 per field
0.48 x 800 = $384 (depreciation in year 3)
Double-declining-balance Method
The double-declining-balance uses a depreciation rate that is double the straight line rate and applies it to the beginning-of-period book value of an asset. The three steps of this method are as follows:
1. Calculate Straight-line rate (100% / useful life periods)
2. Calculate Double-declining-rate (SL rate x 2)
3. Multiply Double-declining-rate by the beginning period book value
To employ this method, it is advisable to produce a double-declining-balance schedule which charts the beginning-of-period book value, depreciation rate, depreciation expense, accumulated depreciation, and book value for each respective period of the asset's useful life. The depreciation expense of each period is subtracted from the beginning-of-period book value to find the beginning-of-period book value of the next period.
It is important to note that all of these methods will produce the same amount of total depreciation at the end of the asset's useful life will be the same. This is ensured by only depreciating as much as needed in the final period of depreciation.
With that, there are now 21 days until Christmas.
