Simple addition and multiplication of textbox values

Hi again Divinedar.

The multiplications work correctly if you convert your text box values to the Double data type first (or to Decimal using CDec). In the code below, the VBA function CDbl() does that (and also I did that for other procedures behind that form). 

Private Sub txtMTLcst_Change()

    If txtMTLcst.Value = "" Then txtMTLcst.Value = 0
    If txtLBRcst.Value = "" Then txtLBRcst.Value = 0
    If txtQTY.Value = "" Then txtQTY.Value = 0
    txtTOTALcst.Value = (CDbl(txtMTLcst.Value) + CDbl(txtLBRcst.Value)) * CDbl(txtQTY.Value)


    sh.Cells(iRow + 1, 6) = txtMTLcst.Value
    'txtMTLcst = Format(txtMTLcst.Value, "$###,##")
End Sub
Private Sub txtLBRhrs_Change()

    If txtLBRhrs.Value = "" Then txtLBRhrs.Value = 0
    If txtPerHRCost.Value = "" Then txtPerHRCost.Value = 0
    txtLBRcst.Value = (CDbl(txtLBRhrs.Value) * CDbl(txtPerHRCost.Value))

    sh.Cells(iRow + 1, 7) = txtLBRhrs.Value

End Sub

Note that I commented out the line formatting Material Cost to "$###,##" (which would require extra code to detect and remove the $ from the string before multiplications were done) and instead changed your form labels to read MTL Cost($) etc.

Also, I added these (repeated) bold bits so the total cost is recalculated if you later change the quantity:

Private Sub txtQTY_Change()
    sh.Cells(iRow + 1, 5) = txtQTY.Value
    If txtMTLcst.Value = "" Then txtMTLcst.Value = 0
    If txtLBRcst.Value = "" Then txtLBRcst.Value = 0
    txtTOTALcst.Value = (CDbl(txtMTLcst.Value) + CDbl(txtLBRcst.Value)) * CDbl(txtQTY.Value)
End Sub

Minor thing- I corrected the heading of column F of the Customer_Order_History worksheet  to read QUANTITY.

I guess in time your labour rate might be a constant and that material costs / labour hours will be stored in you PT- worksheets (and gathered/ presented in the form) but I leave that to you.

Hope this fixes things for you.