Hello I want to know how many days does a woman ovulates .

Every woman is different, so the number of times per 28 day cycle and for how long you ovulate is something only YOU can know. I only ovulate twice a month for one day each. You can buy an ovulation kit at any drugstore. They are very simple to use.

hello i want to know how many days does a woman ovulates .

In the vast majority of cases a woman will ovulate one day a month... general guide is 12 to 16 days before a period is due... but some women will ovulate sooner, some later then the norm. On a few occasions, a woman may release a second egg right afterwards... this is the reason for some sets of twins. In an unusual twist, it is also the reason it can happen that a woman may give birth to two babies at the same time with different fathers.
The egg is viable for about 24 hours, but it is thought the first half of that is best. This makes it difficult to time trying to get pregnant on the day of ovulation as most women don't know exactly the day of ovulation. There are means to determine if you are most likely ovulating, that your body is preparing to ovulate... temping/charting, ovulation kits, checking for cervical changes, but you would need to see your doctor to determine if you are indeed ovulating. It can happen, as well, that a woman will ovulate several months, then skip a month here and there.
In most cases, if a woman is having regular periods, and of childbearing age, she is likely ovulating on a pretty regular basis.
Ovulating and being fertile are not the same thing. A woman may be fertile for several days... this means her body is preparing for ovulation and allows the sperm to hang out waiting for the egg to be released. It is at this time, prior to ovulation, that sperm will be able to survive for a few days... a few hardy souls may survive several days. Otherwise the sperm will die off fairly quickly at other times of the cycle.