i) was it an authorised/approved & paid leave or LWP (Leave without pay)?
ii) did your office treated this 'leave of absence' a 'break-in-service' or there is no problem as it was treated as a spell of 'continuous leave';
iii) have you reported back to your duty after completion of 8 months of ML and is still continue to work with the very same employers?
iv) why you asked this query, are you planning to quit and that's why you are trying to calculate about the gratuity?
28th March 2019 From India, Bangalore