Ovulation calculator

When you are trying to conceive, you need to know when you are fertile! The easiest first step is to calculate when you will likely ovulate. If you have a healthy luteal phase, that will be 14 days before your next period. This ovulation calculator helps you calculate when your next most fertile days are so that you can fall pregnant.

Please select the first day of your last menstrual period:

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Usual number of days in your cycle:

The first date this calculator gives you, is the day before ovulation. That is the most fertile time in your month. The calculator gives you some extra days however, in case you ovulate later.

To however make the most of your cycle, start trying 4 days before the first date this calculator gives you as that is when your fertile window likely opens.

The best way to find out when you will be fertile, is to however chart your cycle. That way you can recognize when your personal fertile window opens and before you ovulate.

To learn how to chart, sign up to my free charting course.