Track Your Ovulation & Fertile Window
Ovulation happens once per menstrual cycle - usually 14 days before your next period. Knowing your fertile window (5 days before ovulation plus ovulation day) helps with conception planning or natural family planning. This calculator estimates your most fertile days.
What Is Ovulation?
Ovulation is the release of a mature egg from the ovary. The egg survives 12-24 hours. Sperm survives 3-5 days in the reproductive tract. This creates a fertile window of 5-6 days per cycle.
The Fertile Window
| Day of Cycle | Fertility |
|---|---|
| Days 1-7 | Low (menstruation) |
| Days 8-9 | Moderate |
| Days 10-14 | High (peak fertility) |
| Days 15-16 | Moderate |
| Days 17+ | Low |
Assumes a 28-day cycle with ovulation on day 14. Adjust for your own cycle length.
How Ovulation Date Is Calculated
For a 30-day cycle, ovulation is around day 16. For a 25-day cycle, around day 11.
Signs of Ovulation
- Cervical mucus changes - clear, stretchy, egg-white consistency
- Slight rise in basal body temperature (0.5-1°F) after ovulation
- Mild one-sided pelvic pain (mittelschmerz)
- Increased libido
- Breast tenderness
- Cervix softens and rises
Best Days to Try to Conceive
- Two days before ovulation - highest conception rate
- One day before ovulation
- Day of ovulation
- Every 1-2 days during the fertile window
Frequently Asked Questions
How accurate is this ovulation calculator?
It is a statistical estimate. Actual ovulation varies by cycle, stress, and health. For accuracy, combine with basal body temperature and ovulation predictor kits.
Can I get pregnant outside the fertile window?
Rarely. Sperm survives 3-5 days, so unprotected sex 5 days before ovulation can still lead to pregnancy.
What if my cycle is irregular?
Track BBT, cervical mucus, and use OPKs. The calculator is less accurate for irregular cycles.
How long does ovulation last?
Ovulation itself is a single event - the egg is released and lives 12-24 hours.
Can you ovulate twice in one cycle?
Very rarely - usually within 24 hours of the first ovulation. This is how fraternal twins happen.
When should I take a pregnancy test?
At least 1 day after your missed period for the most accurate result. Some early tests work 5 days before, but with lower accuracy.