Ovulation Calculator
Estimate your ovulation day, fertile window and next period from your cycle
Enter Your Cycle Details
Most cycles are 21–45 days (average 28).
Your Result
Likely ovulation day
Friday
Fertile window
Sep 13, 2026 – Sep 19, 2026
Next period
Oct 2, 2026
Fertile days (28-day cycle)
About this Tool
This ovulation calculator estimates your fertile window using the standard calendar method: ovulation typically occurs about 14 days before your next period. Enter the first day of your last period and your average cycle length to get your likely ovulation day, 7-day fertile window, and predicted next period.
Common Use Cases
Trying To Conceive
Time intercourse to the 5 days before plus ovulation day, when conception odds are highest.
Cycle Awareness
Understand when fertile-phase symptoms like cervical-mucus changes are most likely.
Period Planning
Predict your next period to plan travel, events and workouts with confidence.
Doctor Visits
Bring a clear cycle summary to fertility or gynecology appointments.
Pro Tips
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Cycles Vary
Stress, illness and travel can shift ovulation — track 3+ cycles for a reliable average length.
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Confirm With Signs
Combine calendar estimates with ovulation test strips or basal body temperature for accuracy.
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Not Contraception
The calendar method alone is unreliable for avoiding pregnancy — sperm can survive up to 5 days.
FAQs
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