Summing up reference a date

[LEG_END]

I have a worksheet that has almost 500,000 lines of data. I want to sum up all the data for each day.

My dates are stored in the format dd/mm/yyyy and are in column M, my values to be summed up are in column H...
and my output should show in column N...

My code so far doesn't seem to work mind once i get to my For/Next statement any ideas?

Sub Fuel******()

Dim WS As Worksheet
Dim MaxRow As Long, I As Long
Dim Tot As Double
Dim Dte As String


Set WS = Sheets("Diesel Collaboration")
WS.Range("M3").Select
MaxRow = WS.Range("M" & WS.Rows.Count).End(xlDown).Row
Tot = 0


WS.Range("L:L").ClearContents
Sheets("Diesel Collaboration").Columns(1).Copy
Sheets("Diesel Collaboration").Columns(12).PasteSpecial xlPasteValues


WS.Range("N4:N1048576").ClearContents


Dte = WS.Cells(4, "M")


For I = 1 To MaxRow + 1
    If WS.Range("M" & I) <> Dte Then
        WS.Cells(I - 1, "H") = Tot
        Dte = WS.Cells(I, "M")
        Tot = 0
    End If
    
    Tot = Tot + Val(WS.Cells(I, "H"))


Next I


MsgBox ("Totals inserted in Col M by date successfully.")


End Sub

 

[DanteAmor]

Try with this.
I guess the records start in row 4

Sub Fuel()


    Dim WS As Worksheet
    Dim MaxRow As Long, i As Long
    Dim Tot As Double
    Dim Dte As String
    
    Set WS = Sheets("Diesel Collaboration")
    
    MaxRow = WS.Range("M" & WS.Rows.Count).End([COLOR=#0000ff]xlUp[/COLOR]).Row
    Tot = 0
    
    WS.Range("L:L").ClearContents
    Sheets("Diesel Collaboration").Columns(1).Copy
    Sheets("Diesel Collaboration").Columns(12).PasteSpecial xlPasteValues
    
    WS.Range("N:N").ClearContents
    
    Dte = WS.Cells(4, "M")
    
    For i = 4 To MaxRow + 1
        If WS.Range("M" & i) <> Dte Then
            WS.Cells(i - 1, "[COLOR=#0000ff]N[/COLOR]") = Tot
            Dte = WS.Cells(i, "M")
            Tot = 0
        End If
        Tot = Tot + Val(WS.Cells(i, "H"))
    Next i
    
    MsgBox ("Totals inserted in Col M by date successfully.")


End Sub

I recommend you do the test with some records. This macro with For-Next for 500,000 will be very slow, I recommend you adjust the macro using objects in memory. But first do the tests with the 500,000 and tell me.