Natural family planning helps identify the phases of a woman's menstrual cycle when she is most fertile, as well as those phases when she is less fertile, and therefore, less likely to become pregnant.
If a woman's cycle is irregular, then natural family planning will be less reliable since it is more difficult to predict when ovulation is likely to occur.
The calculations below are based on the following facts :-
A woman usually ovulates 14 days before her next period. For example, if a woman has a regular 26-day menstrual cycle, counting the first day of her period as day one, then she will usually ovulate on day 12.
The female egg released into the female falopian tubes has only 24 hours to be fertilized by the male sperm.
However, the male sperm can survive for up to seven days in the female cavity.
Fill the details below and press 'Natural Family Planning Details'.
CLICK HERE if you have any ideas for calculators you would like to see added; or improvements to existing ones made. Please tell us of any errors observed!