Calculation

Formula
(Sell Price -Buy Price) x Lot Size x Contract Size (+/- interest) - Commission
= Net Profit

Example 1(HKGOLD)

Trade: 
Client Trade on the same day buy and sell 3 lot 

Buy Price: 
Each Tael HK$6,010

Sell Price: 
Each Tael HK$6,165

Profit and Loss Calculation:
HK$(6,165 - 6,010) X 100 taels x 3 lot = HK$46,500

Example 2 (LLG)

Trade: 
Client Trade on the same day buy and sell 3 lot 

Buy Price: 
Each Tael $656

Sell Price: 
Each Tael $675

Profit and Loss Calculation:
($675-$656) X 100 ounce x 7.8 x 3 lot = HK$44,460