Each month a woman can only get pregnant when an egg is released from the ovary. This is around 14 days from the start of your last period. An egg has a “life span” of about two days.
There is a catch though. The release of the egg determines when your NEXT period will come and is not directly related to your last one. Fortunately most women have a fairly regular cycle and hence the date of the start of the last period gives a useful guide.
There are two reasons people want to know ovulation dates. One is for trying to get pregnant and the other is for those using standard days contraception (also known as rhythm method).
This calculator lets you work out likely “safe” dates if you do not want to get pregnant and are not using other contraception. It is an estimate based on the assumptions of a 28-day cycle and ovulation happening on day 14. It is necessarily conservative as ovulation may occur later or earlier than day 14.
For those wanting to get pregnant the highest chance of doing this is around day 14 so the exact opposite advice applies. If trying to get pregnant this is the best time for intercourse.
To find out the dates for you just click on the date of your last period.