Andy if you have less than $25k in your account you can make 3 roundtrip day trades in a rolling 5 business days. A round trip is a buy and sell in the same day if you dont do both it doesnt count as a round trip. The 4th time you do a round trip in 5 business days you will be tagged as a pattern day trader and they freeze your account for 90 days (i think). If you have over $25k in you account at the begining of the day you can do as many round trips as you want