Question: how to calculate gross profit sum insured?
Answer: Your Insurable Gross Profit for a 12 month Indemnity Period is.
$ Please multiply the above by: a) 150% for an 18 month Indemnity Period. ... 
Your insured Rate of Gross Profit is (Sub Total B divide Sub Total A)
%
Plus the following optional covers.
• Additional Increase in Cost of Working (minimum 10% of Sub Total A) $