DDB function
OriginalCost
The initial cost of the asset.
SalvageValue
The value at the end of the depreciation (sometimes called the salvage value of the asset).
Lifetime
The number of years over which the asset is being depreciated.
Year
The year number for which the depreciation is calculated.
Factor
The depreciation rate factor. If omitted, it is assumed to be 2.
Returns
The depreciation of an asset.
Returns the depreciation of an asset for a given year using the double declining-balance method (or any other factor).
Examples
Returns $4,800. The rate is 2/5, or 40%. The book value at the start of year one is $12,000, and 40% of $12,000 is $4,800.
Returns $2,880. The book value at the start of year two is $12,000 - $4,800 = $7,200, and 40% of $7,200 is $2,880.
Returns $1,320. The book value at the start of year three is $7,200 - $2,880 = $4,320, and 40% of $4,320 is $1,728 — but DDB returns only enough depreciation to reduce the book value to the salvage value — that is, $4,320 - $3,000 = $1,320.
Returns $0. The book value at the start of year four is equal to the salvage value — no further depreciation is possible.