Plinth height is provided to protect the building from dampness which may seep due to the direct contact with the ground. The top of plinth protection is given with damp proof course (DPC) which prevents dampness directly, Plinth height also provide safety against water flooding. Plinth level is is at which the building ends and the super structure starts. The plinth height is between 300mm and 450mm from ground level. Experts suggest that the plinth height of 150mm is better to be adopted from top of the road.

So the answer is 300mm to 450mm.

I hope I answered you.

Feel free to ask any doubts in comments.