What is a Day Trade?
A day trade is counted when you open a position and close it on the same day. An easier way to understand how day trade is count is that the count would +1 when you purchase or short security and then sell or cover the same security on the same trading day.
Therefore, if we buy a security and sell it on a different day, our trade would not be deemed a day trade. But, what if we bought the same security twice in a row and sold them all in once? Or what if our orders are partially filled in two separate times? You might find the answer in the following examples.
Examples
Normal
You open and close a position in the same day. [Day trade count +1]
Situation 1 (1 open 1 partial close)
You open a position and close the position partially. [Day trade count+1]
Situation 1 (continued)
You close the remaining position on the same day. [Day trade count = 1+0)
Situation 2 (2 Open 1 Close)
You open a position twice and close them in once. [Day trade count +2]
Situation 3 (1 Open with partial fills 1 Close)
You open a position with two partial fills, and close them all in once. You did not modify your order. [Day Trade count+1]
Situation 4 (1 Open with partial fills (modified) 1 Close)
You open a position with two partial fills, and close them all in once. You did modify your order. [Day trade count +2]
If you are thinking of ways to avoid the PDT rule, you could check out this article: How to avoid the PDT rule with a Margin account?