How the calculator estimates ovulation
Ovulation is about 14 days before your next period. The phase after ovulation is fairly constant for most women, so we count back from your next period, not forward from the last.
The fertile window is six days. The five days before ovulation and ovulation day itself, according to a study in the New England Journal of Medicine.
Test on the day your period is due. Home pregnancy tests give a clearer result from the day your period is expected.
Not a method of birth control. Ovulation can come earlier or later in any cycle, so don’t rely on the calculator to avoid pregnancy.
FAQ
When do I ovulate in a 28-day cycle?
Around day 14 counting from the first day of your period, with fertile days from day 9 to day 14.
My cycle is irregular. Will this work for me?
It gives an estimate, but a less accurate one. Home ovulation tests that measure LH are more precise, or talk to your doctor.
Can timing intercourse choose the baby’s sex?
There’s no scientifically proven way to do that. The same study that defined the fertile window found no link between timing and the baby’s sex.
What are the signs of ovulation?
You may notice clear, stretchy discharge like egg white, and a slight rise in body temperature after ovulation. Signs vary from woman to woman.
Do you store the date I enter?
No. Everything is calculated in your browser; no date is sent anywhere.