DDB function
This article describes the formula syntax and usage of the DDB function in Microsoft Excel.
Description
Returns the depreciation of an asset for a specified period using the doubledeclining balance method or some other method you specify.
Syntax
DDB(cost, salvage, life, period, [factor])
The DDB function syntax has the following arguments:

Cost Required. The initial cost of the asset.

Salvage Required. The value at the end of the depreciation (sometimes called the salvage value of the asset). This value can be 0.

Life Required. The number of periods over which the asset is being depreciated (sometimes called the useful life of the asset).

Period Required. The period for which you want to calculate the depreciation. Period must use the same units as life.

Factor Optional. The rate at which the balance declines. If factor is omitted, it is assumed to be 2 (the doubledeclining balance method).
Remarks

The doubledeclining balance method computes depreciation at an accelerated rate. Depreciation is highest in the first period and decreases in successive periods. DDB uses the following formula to calculate depreciation for a period:
Min( (cost  total depreciation from prior periods) * (factor/life), (cost  salvage  total depreciation from prior periods) )

Change factor if you do not want to use the doubledeclining balance method.

Use the VDB function if you want to switch to the straightline depreciation method when depreciation is greater than the declining balance calculation.
Example
Copy the example data in the following table, and paste it in cell A1 of a new Excel worksheet. For formulas to show results, select them, press F2, and then press Enter. If you need to, you can adjust the column widths to see all the data.