Ovulation calculator
Find your most fertile days for the next 3 cycles, plus when your next period and test day are.
Your cycle is the number of days from the first day of one period to the first day of the next.
When am I most fertile?
You're most fertile in the 6 days that end on the day you ovulate, and especially the 2–3 days right before. Ovulation usually happens about 14 days before your next period. So with a 28-day cycle, that's around day 14. With a 32-day cycle, it's around day 18.
How we calculate this
Next period = first day of last period + your cycle length. Ovulation = next period − 14 days. Fertile window = the 5 days before ovulation plus ovulation day. This is the calendar method. It's an estimate, because ovulation can shift from month to month. It is not a form of birth control.
Questions moms ask
Can I get pregnant outside the fertile window?
It's much less likely, but ovulation can come earlier or later than expected. That's why this calendar should never be used as birth control.
What if my cycles are irregular?
Use your average cycle length, but the dates will be less certain. Ovulation test kits, which check your urine for a hormone surge, can help you find your fertile days.
When can I take a pregnancy test?
For the most reliable result, test on the day your period is due or later. Testing earlier can give a false negative.
How long does sperm live?
Sperm can live up to about 5 days inside the body. That's why the days before ovulation count as fertile days.
Related tools
This tool gives an estimate, not medical advice. Every pregnancy and every baby is different. If you're worried about anything, talk to your doctor or midwife.