Ovulation Calculator
Predict ovulation and fertile days
Formula
Ovulation ≈ Next Period - 14 days
Fertile: 5 days before + ovulation day
Fertility Timeline
| High fertility | 2-3 days before O |
| Peak | Day before O |
| Egg viable | 12-24 hours |
| Sperm viable | Up to 5 days |
Related
Complete Guide to Ovulation Calculator
Ovulation is the release of an egg from the ovary. Understanding your ovulation timing helps you conceive or avoid pregnancy.
When Does Ovulation Occur?
Typically 14 days before your next period. For a 28-day cycle, that is day 14. For a 30-day cycle, it is day 16.
Signs of Ovulation
- Clear, stretchy cervical mucus
- Slight temperature rise after ovulation
- Mild cramping (mittelschmerz)
- Positive ovulation predictor kit
Frequently Asked Questions
Typically 14 days before your next period. For a 28-day cycle, that is day 14. Track your cycle length for better predictions.
The 6-day period when pregnancy is possible: 5 days before ovulation plus ovulation day. This accounts for sperm survival and egg viability.
They predict based on averages, but actual ovulation can vary by several days. Use with physical signs or OPK tests for better accuracy.
Very unlikely. The egg only survives 12-24 hours, and sperm up to 5 days. Outside this window, conception is essentially impossible.
Tests that detect the LH surge 24-36 hours before ovulation. They are more accurate than calendar methods for timing intercourse.
Yes. Ovulation is typically 14 days before your next period, not 14 days after the last. Longer cycles mean later ovulation.
Yes. Stress, illness, travel, and weight changes can delay or prevent ovulation, making predictions less accurate during unusual months.