Hello,

Divide your NATA score by 2  and add your board percentage (out of 100) and then divide the total  by 2 or simply divide the NATA score by 4 and 12 th percentage divided by 2 and then add them to get the merit mark.

For example,

If you scored 146 in NATA and 85 %  in your boards,then the merit mark will be :

(146/2+85)/2=158/2 = 79

OR

146/4+85/2= 36.5+42.5= 79

Hope it helps

Good luck!