Fertile Window & Best Days to Conceive
✓ Fertile Window - 7-day conception window
✓ Peak Fertility Days - Highest conception chance (30-33%)
✓ 6-Month Calendar - Track upcoming cycles
✓ Day-by-Day Probability - Conception odds each day
Normal range: 21-35 days (average: 28 days)
Average: 3-7 days
💡 How to track your cycle:
Count from day 1 of your period to day 1 of your next period. Track for 3 months to get your average.
Enter your cycle details to calculate
An Ovulation Calculator predicts your most fertile days by calculating when you ovulate during your menstrual cycle. Ovulation occurs when an egg is released from your ovary, typically 14 days before your next period.
Our calculator identifies your fertile window (6-7 days when conception is possible), peak fertility days (highest conception probability 30-33%), ovulation date, and tracks your next 6 cycles with day-by-day conception probability breakdown.
Ovulation is when your ovary releases a mature egg into the fallopian tube. This egg survives for 12-24 hours after release.
• Happens once per cycle
• Usually 14 days before next period
• Egg lives 12-24 hours
• Most fertile time of month
Your fertile window is the 6-7 days when pregnancy is possible. It includes 5 days before ovulation + ovulation day + 1 day after.
• Lasts 6-7 days total
• Sperm can live 5 days
• Egg lives 12-24 hours
• Best time to try conceiving
The 2 days before ovulation have the highest conception probability (30-33%). This is your peak fertility window.
• 2 days before ovulation
• 30-33% conception chance
• Optimal timing for intercourse
• Sperm ready when egg releases
| Day Relative to Ovulation | Conception Probability | Fertility Status |
|---|---|---|
| 5 days before | 10% | Low fertility |
| 4 days before | 15% | Moderate fertility |
| 3 days before | 25% | High fertility |
| 2 days before | 30% | Peak fertility |
| 1 day before | 33% | Peak fertility |
| Ovulation day | 20% | High fertility |
| 1 day after | 10% | Low fertility |
| 2+ days after | <5% | Very low |
💡 Key Finding: The 2 days before ovulation offer the highest conception chance (30-33%) because sperm are already waiting when the egg is released.
Cervical Mucus Changes
Clear, stretchy, egg-white consistency (most fertile)
Basal Body Temperature Rise
0.5-1°F increase after ovulation
Cervix Position
Higher, softer, and more open
Increased Sex Drive
Natural boost in libido
Mild Pelvic Pain
Mittelschmerz - one-sided cramping
Breast Tenderness
Sensitive or sore breasts
Light Spotting
Ovulation bleeding (rare)
Bloating
Mild abdominal bloating
If your cycle length varies by more than 7-9 days each month, you have irregular cycles. This makes ovulation harder to predict but not impossible.
The best time is 2 days before ovulation. This gives sperm time to travel to the fallopian tube and be waiting when the egg is released.
Optimal Timing:
Ovulation itself lasts 12-24 hours - this is how long the egg survives after being released. However, your fertile window lasts 6-7 days.
Technically no, but irregular cycles, early ovulation, or cycle variations can shift your fertile window. That's why some pregnancies occur from sex outside the "predicted" fertile window.
Why it can happen:
💡 Tip: If trying to conceive, have sex every 2-3 days throughout your cycle to ensure you don't miss the fertile window.