Magento: How to get last order id

There are many ways to get last order id:

1.  From checkout session:

    $lastOrderId = Mage::getSingleton('checkout/session')
                   ->getLastRealOrderId();

    $orderId = Mage::getModel('sales/order')
               ->loadByIncrementId($lastOrderId)
               ->getEntityId();

Above solution will not work, if you want to get last order id in admin.

For this you can try this solution:

2.  From model:

$orders = Mage::getModel('sales/order')->getCollection()
     ->setOrder('increment_id','DESC')
     ->setPageSize(1)
     ->setCurPage(1);

$orderId = $orders->getFirstItem()->getEntityId();

But this method will not work, if there are multi store in a single magento setup. So a better solution would be:

$orders = Mage::getModel('sales/order')->getCollection()
     ->setOrder('created_at','DESC')
     ->setPageSize(1)
     ->setCurPage(1);

$orderId = $orders->getFirstItem()->getEntityId();

That's all.. Enjoy.. :)