The most fertile days in the cycle will be at least 3 days before, during and some days after ovulation. This will be the best time for you to try and conceive. Sperm will survive for 3 to 5 days while the egg will last for 12 to 24 hours. You are fertile for about 5 to 7 days. In case you are not sure about your ovulation, you can also use an ovulation kit to make sure.