You may refer to the "Day Trades Left (T, T+1, T+4)" counter on the Available for Trading section of your Account Window within TWS to determine when you will be able to open a new position again.

Please note, if you don't see the "Day Trades Left", expand the Available for Trading section using the green plus (+) sign on the right. The number of day trades available for the next 5 days will be listed in parenthesis, the first number listed is always the current day: Day Count T = TodayT+1 = One day after todayT+2 = Two days after todayT+3 = Three days after todayT+4 = four days after today The numbers begin at 3 and move from right-to-left. If you execute a day trade, then all numbers will be reduced by one. If T=0, then your account has executed three day trades in the past five days, and you will be unable to open a new position today. You will be able to open a new position when T = 1, 2, or 3.

As an example, if the window reads (0,0,1,2,3), here is how to interpret this information: If today was Wednesday, the first number within the parenthesis, 0, means that 0-day trades are available on Wednesday. The 2nd number in the parenthesis, 0, means that no day trades are available on Thursday. The 3rd number within the parenthesis, 1, means that on Friday 1-day trade is available. The 4th number within the parenthesis, 2, means that on Monday, if 1-day trade was not used on Friday, and then on Monday, the account would have 2-day trades available. The 5th number within the parenthesis, 3, means that if no day trades were used on either Friday or Monday, then on Tuesday, the account would have 3-day trades available.

See also: How do you count the Day Trades? and How do I request a Pattern Day Trading reset?