What are the possibilities of ovulating a day to 5 days after ending period on a regular 30 day cycle?

Ovulation: Low possibility but still possible. Usually ovulate 14 days before your next period, so in a 30 day cycle that is day 15-16. Depending on how long your period is(5-8 days) there may be a 3-6 day gap, but there is always some variation. Sperm can live up to 3-5(7) days in vaginal tract so if you are active between days 10 and 16 sperm may be viable an lead to fertilization.Use ovulation kit.

Unlikely: Ovulation usually occurs around the 14th day after your cycle begins. It is unlikely that you would ovulate so close to a period ending.