I want to upgrade my laptop hard drive I want a 3.5 inch 2 TB sata but can only find a 2.5 inch. Will a 2.5 inch work for a 3.

There aren't any laptops that I am familiar with that use a 3.5 inch disk. They are too thick. 2.5 is the standard form factor for disks in laptops.
 
3.5 in for external storage for l/n only. 2.5 in drives only in laptops/notebooks. Ya can't find what doesn't exist.
Walt Prill