Understanding your calculation
Method, example and limitations
How the calculation works
Ovulation estimates use the cycle length and period start date to suggest a likely ovulation window. This method assumes a reasonably regular cycle.
Example to check
For an illustrative 28-day cycle beginning on day 1, a common estimate places ovulation around day 14; a different cycle length shifts the estimate.
Before using the result
Ovulation does not always happen on the predicted day. This calendar estimate is not a reliable contraceptive method or a fertility diagnosis.