How to calculate quantity of WAL in db without archiving?
There is no easy way as such to get a count of the WAL Files. But what you could do is run the SQL below at a certain time and then run it again 24 hours later. Getting the difference should give you some indication of the number.

SELECT COUNT(*) FROM pg_ls_dir('pg_xlog') WHERE pg_ls_dir ~ '^[0-9A-F]{24}';


Some details Postgreal Admi functions and pgDash blog.