computation of PGBP

*Take the Net Profit mentioned in the Books of Accounts as the base value. 

* Add back all the deductions that are disallowed under the income tax act (Refer Section 37, 14) which you have already availed in the P&L account maintained as a part of books of accounts. 

* Subtract the expenditures that are allowed as per the provisions of income tax laws (Refer section 32, 35, 36). 

For details refer: 

1. computation-of-profits-gains-of-business-or-profession  or

2. profit_and_gains_from_business_or_profession