Hi there, Lu!
Thanks for stopping by the Disney Parks Moms Panel with your question. I'm more than happy to help!
The cost to upgrade your 7-Day Theme Park Ticket to an Annual Pass will depend on what type of ticket you purchased. If you selected the Park Hopper option, the Water Park Fun & More option or both of these options, then the cost to upgrade would be less. Also, ticket prices are always subject to change so what I would suggest is that you compare the price of the
Theme Park Ticket that you purchased with the price of an
Annual Pass and subtract the difference. This will give you an idea of what you can expect to pay to upgrade your ticket. Be sure to stop by a Guest Relations window at any of the Theme Parks or Downtown Disney prior to your ticket's expiration to upgrade it. Once your ticket expires, you will not have the option to upgrade.
I'm sure you will enjoy all of the benefits of being a Walt Disney World Resort Annual Passholder and will find even more opportunities to visit (if you're like me)!
Wishing you a magical year,
~Carrie