When trading P&L is treated as business income, then is it mandatory to calculate turnover

Turnover is only used to establish whether or not tax audit is applicable. 

Your tax liability is unaffected by your turnover.

The method to calculate trading turnover is different for each type of trading i.e. Equity Intraday, Equity Delivery, Equity F&O, Currency Trading, Commodity Trading, etc.

Methods to Calculate Trading Turnover


Trading Type
Trading Turnover
Equity Intraday Trading
 Absolute Profit/Loss
Equity Delivery Trading
 Sales Value
Equity F&O Trading
 Absolute Profit/Loss 
Currency Trading (Equity / Intraday / F&O)
 Absolute Profit/Loss
Commodity Trading (Equity / Intraday / F&O)
 Absolute Profit/Loss