Ovulation Calculator
Predict ovulation dates and fertile window to maximize chances of conception or avoid pregnancy.
Typical range: 21-35 days. Average is 28 days.
About Ovulation
Ovulation is when an ovary releases an egg. This typically occurs about 14 days before your next period starts. The fertile window is the 6 days leading up to and including ovulation day.
Note: This calculator provides estimates based on average cycles. For precise tracking, consider using ovulation predictor kits or monitoring basal body temperature.
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How to Use This Calculator
- Remember the first day of your last menstrual period
- Select that date using the date picker
- Enter your average cycle length (number of days from first day of one period to first day of next)
- If unsure, use 28 days as a typical average
- Click 'Calculate Ovulation' to see your results
- Review your estimated ovulation date
- Note your fertile window (best days for conception)
- See your next expected period date
- Check when to take a pregnancy test if needed
Formula
Ovulation Date = LMP + (Cycle Length - 14) days; Fertile Window = Ovulation Date ± 5-6 days; Next Period = LMP + Cycle Length; Most Fertile Days = 2 days before ovulation to day of ovulation
Frequently Asked Questions
When am I most fertile?▼
You're most fertile during the 6-day window ending on ovulation day. The highest pregnancy rates occur when intercourse happens 2 days before ovulation, the day before ovulation, and on ovulation day. Sperm can survive up to 5 days, while the egg lives 12-24 hours.
How accurate is the ovulation calculator?▼
This calculator assumes ovulation occurs 14 days before your next period, which is accurate for most women with regular cycles. However, ovulation timing can vary by ±2 days. For precise ovulation detection, use ovulation predictor kits (OPKs) or track basal body temperature.
What if my cycle is irregular?▼
If your cycle length varies by more than 7-9 days month to month, this calculator may be less accurate. Track your cycles for 3-6 months to find your average length. Consider using ovulation predictor kits, cervical mucus monitoring, or consulting a healthcare provider.
When should I take a pregnancy test?▼
For most accurate results, take a pregnancy test on or after the first day of your missed period (shown in the results). Some sensitive tests can detect pregnancy 8-10 days after ovulation, but false negatives are common if testing too early.