Val(ProjDurConv(duration,pjdays)) to display days
Calculateelapsed days
IIf(ProjDateDiff(Start,[Status Date])/480>=Val(ProjDurConv([Baseline Duration],pjDays)),
Val(ProjDurConv([Baseline Duration],pjDays)),IIf(DateDiff(“d”,[Baseline Start],[Status Date])
<=0,0,ProjDateDiff(Start,[Status Date])/480))

Calculate the planned percentage complete

Formula: Number2/Number1

Format the percentage column
Another column Formula: Format(Number3, “0%”)

Also see:

https://niksprojects.com/2016/06/05/ms-project-actual-vs-planned-complete/
https://www.youtube.com/watch?v=UwCPwR4hToA