Ovulation Calculator
Find your ovulation date and fertile window based on your cycle
Cycle Information
First Day of Last Period (LMP)
Average Cycle Length (days)
days
Typical range: 21–35 days. Most common: 28 days.
Luteal Phase Length (days)
days
Usually 12–14 days. The phase after ovulation until next period.
Next 3 Fertile Windows
| Cycle | Fertile Window |
|---|
Ovulation Date
—
—
Fertile Window Start—
Fertile Window End—
Next Period (est.)—
Est. Due Date—
Understanding Your Cycle
Ovulation typically occurs 14 days before your next period (the luteal phase length). The fertile window is the 5 days before ovulation plus ovulation day itself — sperm can survive 3–5 days in the reproductive tract, while an egg is viable for only 12–24 hours after release.
This calculator uses the calendar method and provides estimates based on average cycle patterns. Actual ovulation can vary due to stress, illness, weight changes, and other factors. For conception, track basal body temperature or use LH ovulation predictor kits for more precision.
lightbulb Signs of Ovulation
1Cervical mucus becomes clear, stretchy (egg-white)
2Basal body temperature rises ~0.2–0.5°C after ovulation
3Mild pelvic pain or cramping (mittelschmerz)
✓ Positive LH surge on ovulation predictor kit