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|