How many days does a womans egg last?

A woman's egg, or oocyte, is viable for fertilization for about 12 to 24 hours after ovulation. If it is not fertilized within this time frame, it will deteriorate and be absorbed by the body. The overall menstrual cycle, however, lasts about 28 days on average, which includes the time leading up to ovulation and the subsequent changes in the reproductive system.