Dwn4BassAlan

Really depends on what you're looking for and what you mean by enclosure calculator. Torres is good, Winisd is good for seeing how the enclosure will generally behave, hornsrep is really powerful but has a steep learning curve. I've heard good things about Bassbox Pro and Term lab software but those are paid for programs while the first three I named are free. 

just need a simple and easy one for now, just building a temporary 1-day box for a short demo, nothing fancy