Hey aspirant, for calculation of cutoff for CBSE you should normalise your marks,follow the below steps.

• Identify the highest marks for physics, maths & chemistry as a, b, c respectively
• Let your phy, maths & che marks be x, y, z
• now the formula is as follows

(x/a)*50 + (y/b)*100 + (z/c)*50 = your cutoff marks out of 200