Therefore, finding the best lot size with a tool like a risk management calculator or something with a desired output can help you determine the desired lot size based on the size of your current accounts, whether practice or live, as well as help you understand the amount you would like to risk. actually lot totally depand on you invested amount , i invested $500 so 1:20 is the best lot for me and reasonable it not too high not too low , in trading market you have to play like then less in put more output