I've seen varying equity percentages pre and post dilution and was wondering what the typical equity compensation is for a CTO of an early stage software company (already incorporated with users and product market fit) that already has an MVP partially built out.

Basically this company already has a web version of this product that has over 4000 users and would like to build a mobile app version with a lot of the basic tech already built out from the web version. If they were to bring someone on to build out the application and help improve other tech, what percentage equity share should that "CTO" have?