vba script to calculate data across multiple columns

Hi all,

i have a rather large data sheet that i need to perform a calculation on by a fixed amount per column

i have around 300 columns of data, with around 600 rows, i have written this script which performs the calculation on a single column of data, but need to expand it to cover all columns of data

Sub Macro1()
'
' Macro1 Macro
'
Dim LastRow As Long
Dim i As Long
LastRow = 111
    For i = 3 To LastRow
      Range("D" & i).Value = Range("D" & i).Value / Range("D1").Value
    Next i
'
End Sub

here is a sample of my dataset

4.7239 4.7239 4.7239 2.3021
COmpany1 Company2 Company3 Company4
-203222 300000 2000000 -4443322
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0