DDB(cost, salvage, life, period [,factor])

Returns the depreciation of an asset in a single period (double or triple declining balance method) (Double).

cost	The initial cost of the asset (Double).
salvage	The value at the end of its useful life (Double).
life	The length of useful life of the asset (Double).
period	The period you want to calculate the depreciation over (Double).
factor	(Optional) The number indicating the type of declining balance to use: 2 - double declining balance depreciation (default) 3 - triple declining balance depreciation

REMARKS

* The "cost", "salvage", "life, "period" and "factor" must all be positive numbers.
* The "life" and "period" arguments must be expressed in the same units (days, months, years).
* If "factor" is left blank, then 2 is used.
* If "factor" = 2, then the double declining balance method is used.
* If "factor" = 3, then the triple declining balance method is used.
* The double declining balance method computes depreciation at an accelerated rate. Depreciation is highest in the first period and decreases in successive periods.
* You can use the SLN function to return the straight-line depreciation of an asset over a single period of time.
* You can use the SYD function to return the sum-of-years' digits depreciation of an asset.
* The equivalent Excel function is Application.WorksheetFunction.DDB
* The equivalent .NET function is Microsoft.VisualBasic.Financial.DDB
* For the Microsoft documentation refer to docs.microsoft.com

Debug.Print Ddb(500, 0, 1, 1)    '= 500  

Debug.Print Ddb(500, 0, 2, 1)    '= 500  
Debug.Print Ddb(500, 0, 2, 2)    '= 0  

Debug.Print Ddb(500, 0, 3, 1)    '= 333.333  
Debug.Print Ddb(500, 0, 3, 2)    '= 111.111  
Debug.Print Ddb(500, 0, 3, 3)    '= 37.037  

Debug.Print Ddb(10000, 9000, 1, 1)    '= 1000  
Debug.Print Ddb(10000, 9000, 2, 1)    '= 1000  
Debug.Print Ddb(10000, 9000, 3, 1)    '= 1000  
Debug.Print Ddb(10000, 9000, 10, 1)   '= 1000  

Debug.Print Ddb(30000, 7500, 10, 1)   '= 6000  
Debug.Print Ddb(30000, 7500, 10, 10)  '= 0  

Debug.Print Ddb(10000, 500, 24, 12)   '= 319.997