Calculate grand total on order

Question

I know grand total is calculated on quote, I would like to find out is there a way to create an order object, add items to it and then get it's grand total without just manually adding item prices to get sum. Also this needs to be done without saving the order.

Answer 1

To calculate and process the grand total you need to follow these

$quote = Mage::getSingleton('checkout/session')->getQuote();
    $address = Mage::getSingleton('checkout/session')->getQuote()->getShippingAddress();
    $address = Mage::getSingleton('checkout/session')->getQuote()->getBillingAddress();
    $quote = $address->getQuote();
    $session= Mage::getSingleton('checkout/session');    
                $items = $session->getQuote()->getAllItems();
        //$items = $quote->getAddressItems($items);
    //echo '<pre>'; print_r($items);

    if(Excellence_Fee_Model_Fee::canApply($address)){
                 //$exist_amount = $quote->getFeeAmount();
                    // $fee = 1000;
                        //$fees = $fee * $result;
                    $balance = 1000;
                        //          $balance = $fee;

                        //$this->_setAmount($balance);
                        //$this->_setBaseAmount($balance);
                        $address->setGrandTotal($balance);

                        $address->setFeeAmount($balance);

                        $address->setBaseFeeAmount($balance);
                        $quote->setGrandTotal($balance);
                        $quote->setBaseGrandTotal($balance);
                        //echo '<pre>'; print_r($quote);
                        $quote->setFeeAmount($balance);
                        //echo '<pre>'; print_r($quote);

                        $address->setGrandTotal($address->getGrandTotal() + $address->getFeeAmount());
                        //echo '<pre>'; print_r($address);
                        $address->setBaseGrandTotal($address->getBaseGrandTotal() + $address->getBaseFeeAmount());
                        //$address->getGrandTotal();
                    //echo '<pre>'; print_r($address);
                    echo  Mage::getSingleton('checkout/cart')->getQuote()->getGrandTotal();

This is working on checkout and cart page to update the grandtotal. Hope this will help you and you find a correct solution.

Answer 2

without just manually adding item prices to get sum.

Magento does not provide a built-in function to calculate the totals as it does for quotes (collectTotals). The above would be approach that comes to mind. Of course it misses things like taxes, discounts, shipping, etc so if possible I would look into what Tim suggests using the quote object instead.