Question

I need to create a fifo function for price calculation.

I have a table with the following layout:

Purchase_date   Quantity  Purchase_Price 
----------------------------------------
2011-01-01      1000      10
2011-01-02      2000      11
......

Sale_date       Quantity  Costprice
----------------------------------------
2011-02-01      50        =fifo_costprice(...

the Fifo formula works like:

fifo_costprice(Q_sold_to_date as float, Quantity_purchased as range
               , Purchase_Prices as range) as float

How do I do this in Excel VBA?

Answer 1

Here’s what I came up with to start, it doesn’t do any error checking and date matching, but it works.

Public Function fifo(SoldToDate As Double, Purchase_Q As Range, _ 
                     Purchase_price As Range) As Double
Dim RowOffset As Integer
Dim CumPurchase As Double
Dim Quantity As Range
Dim CurrentPrice As Range

  CumPurchase = 0
  RowOffset = -1
  For Each Quantity In Purchase_Q
    CumPurchase = CumPurchase + Quantity.Value
    RowOffset = RowOffset + 1
    If CumPurchase > SoldToDate Then Exit For
  Next
  'if sold > total_purchase, use the last known price.
  Set CurrentPrice = Purchase_price.Cells(1, 1).offset(RowOffset, 0)
  fifo = CurrentPrice.Value
End Function