DDB Function Example

Using the double-declining balance method, this example returns the depreciation of an asset for a specified period given the initial cost (InitCost), the salvage value at the end of the asset's useful life (SalvageVal), the total life of the asset in years (LifeTime), and the period for which the depreciation is calculated (Depr), also in years.

   Const YRMOS = 12                       ' Number of months in a year.
   Fmt = "###,##0.00"
   InitCost = InputBox("What's the initial cost of the asset?")
   SalvageVal = InputBox("Enter the asset's value at end of its life.")
   MonthLife = InputBox("What's the asset's useful life in months?")
   Do While MonthLife < YRMOS             ' Ensure period is >= 1 year.
      MsgBox "Asset life must be a year or more."
      MonthLife = InputBox("What's the asset's useful life in months?")
   LifeTime = MonthLife / YRMOS           ' Convert months to years.
   If LifeTime <> Int(MonthLife / YRMOS) Then
      LifeTime = Int(LifeTime + 1)        ' Round up to nearest year.
   End If
   DepYear = CInt(InputBox("Enter year for depreciation calculation."))
   Do While DepYear < 1 Or DepYear > LifeTime
      MsgBox "You must enter at least 1 but not more than " & LifeTime
      DepYear = InputBox("Enter year for depreciation calculation.")
   Depr = DDB(InitCost, SalvageVal, LifeTime, DepYear)
   MsgBox "The depreciation for year " & DepYear & " is " & Format(Depr, Fmt) & "."