Programmatically calculate tax on shipping cost in magento
devm.com.np

<?php
        $order 
$this->getOrder();

        
$shippingTaxClassId Mage::getStoreConfig('tax/classes/shipping_tax_class',$order->getStoreId());        
        
$customerGroupId $order->getCustomerGroupId();
        
        
$group Mage::getModel('customer/group')->load($customerGroupId);
        
$custTaxClassId $group->getTaxClassId();
        
        
$store Mage::getModel('core/store')->load($order->getStoreId()); 
        
        
$taxCalculationModel Mage::getSingleton('tax/calculation');       
        
$request $taxCalculationModel->getRateRequest($order->getShippingAddress(), $order->getBillingAddress(), $custTaxClassId$store);        
            
        
$shippingTaxPercent $taxCalculationModel->getRate($request->setProductClassId($shippingTaxClassId));
?>