How to calculate total user profile completness and pass it with laravel attributes?

I have main user table and it has relation table like profile, usereducation, userskill, userexperience. the last 3 table are nullable and it will be multiple data like user has multiple usereducation and so on. so i want to calculate the total of this table field as 100 and count the completeness of this table and - from the total in laravel how can do that .