CalculatorsSleep, cycle and pregnancyOvulation calculator
Ovulation calculator
Estimate your fertile window and next period for the next three cycles. Nothing is saved or sent anywhere.
Put in your numbers, and your result appears here.
How the estimate works
Ovulation usually happens about 14 days before your next period, whatever your cycle length. So we count back from when your next period is due. Pregnancy is possible in the six days ending on ovulation day, because sperm can survive for days and an egg for less than one.
That window is an average. In real life ovulation moves, even in very regular cycles, so a calendar can only ever give you an estimate.
If you're trying to conceive
Many doctors suggest simply having sex every two or three days through your cycle, which takes the pressure off timing. Ovulation test strips and tracking your temperature can narrow things down.
The usual advice is to see a specialist after a year of trying if you're under 35, or after six months if you're 35 or over, and sooner if your cycles are irregular or you know of a problem.
Questions
Can I use this as contraception?
No. Calendar estimates aren't reliable enough to prevent pregnancy.
My cycles are irregular. Will this work?
Not well. It assumes a steady length. Cycles under 24 or over 35 days, or that change a lot, are worth raising with your doctor.
When am I most fertile?
The chance climbs through the window and is highest in the last two or three days of it, up to and including ovulation.
Do you store my dates?
No. They stay in this browser tab. They're not sent to us, saved or put in the address bar.
Sources
Written by LifeFrom from the sources above, and not yet reviewed by a clinician. An estimate for your own understanding: it doesn't diagnose or treat anything, and it doesn't replace your doctor.
