Mardi Gras is February 25 in 2020. New Orleans will be most crowded and expensive at that time. Not so much from the 26th on.

If you're still considering New Orleans as part of your itinerary you might want to time your visit to either engage or avoid, depending on your preferences and budget.

Mobile, the Mississippi Gulf Coast, and even Pensacola also have some Mardi Gras events.