A fertility calculator is a simple tool used to predict the date of a ovulation, which is when a woman is most fertile and able to conceive a child. A fertility calculator is not intended to be used as a method of contraception, but rather by people who are trying to conceive. Usually, fertility calculators are used in conjunction with other methods of fertility monitoring, such as by monitoring cervical mucus or body temperature changes.
A fertility calculator may be found on many different websites online for free. It generally only requires the user to enter information such as the date of her last period, as well as the average length of her menstrual cycle. Some calculators may also ask whether the couple wants to try for a girl or boy, though this is of course not always able to be controlled. This type of calculator will typically only work for women whose menstrual cycles are between 21 and 35 days long; 28 days is the average length of a menstrual cycle.
This type of simple tool can be a good first step in predicting ovulation. Most women ovulate about halfway through their menstrual cycles, but tracking this process from month to month can give an individual a very good idea of her ovulation dates. Each woman is different, and it can be difficult to determine when ovulation occurs each month without performing some sort of personal tracking, rather than just relying on a fertility calculator that uses simple estimation.
A fertility calculator will indicate the few days during the month where a woman is most likely to get pregnant. Usually, this is shown on a small calendar to make it easier to view. If not, it is possible to create a calendar on the computer, or to simply make notations in a datebook to reference later.
A woman can also track monthly changes in her cervical mucus, which indicates when ovulation has occurred. Taking the temperature every morning upon waking is known as the basal body temperature method, and changes in this morning temperature can indicate ovulation as well. In addition, ovulation test kits can be purchased at drug stores, which can be used at home to indicate when ovulation is occurring. Using some or all of these methods together can be helpful when trying to get pregnant; if they are ineffective, it may be necessary to visit a doctor for further fertility testing.