How many days are for ovulation each cycle?

ONE. You usually only olvulate once a month. In a 28 day cycle that is usually day 14.
Less than one. When ovulation occurs the egg must be fertilized in 12 hours or it dies off. Sperm can live for several days in the cervical mucus so having intercourse a few days before ovulation can still result in pregnancy. 24 hours after ovulation there is no more chance for pregnancy that month. The ovulation predictor kit urine test will tell you that ovulation will occur in 24-48 hours.