*********** U need to Learn Do your homework by yoursellf ********** double total = Convert.ToDouble(TextBox_item_rented.Text) * Convert.ToDouble(TextBox_cost_per_hour.Text); TextBox_total=total.ToString(); MessageBox.Show("Total Cost for customer "+ TextBox_cust_name.Text + "= " + total); *********** U need to Learn Do your homework by yoursellf ********** :sigh: :zzz: :zzz: :zzz: