Thank you for asking to answer!! :)
XAT cutoff calculation depends on:
-The difficulty level of XAT
-No. of XAT test takers
- Previous cut off trends
-Seats Available overall
-Reservation as well
And keeping the above factors in mind, you shall get your percentile.
there are multiple score calculator available online. prefered ones are from TIME, Career Launcher,IMS etc.
check there
best of luck