Your real estate agent will try to schedule both "closings" on the same day (or back-to-back) to minimize the time you're "homeless" or paying double.
You only have to move once, and you can take your time prepping your old house for sale without living in a construction zone. buying a house while selling another
Talk to your lender to see exactly how much you’ll walk away with after the sale. Your real estate agent will try to schedule