Can I calculate/preview a new subscription total in Salesforce?

We do offer a Calculate button, but whether it is visible to you depends on whether or not the new subscription you are creating has add-ons attached to it. 


If the subscription doesn't have any add-ons attached, then the Calculate button will not be visible as it is not necessary in this case - the subscription total will match the price for the subscription itself.


If the subscription does have at least one add-on attached to it, then the Calculate button will become visible to you, as can be seen in this sample screenshot: 



Then, all you need to do is click that button to preview the total for that subscription.