Ovulation & Fertile Window Calculator
Calculate your most fertile days, estimated ovulation date, and plan ahead with upcoming cycle projections based on your menstrual patterns.
Menstrual Cycle Details
Most women have a 28-day cycle, but normal cycles range from 21 to 35 days.
Days between ovulation and the next period (standard average is 14 days).
Medical Disclaimer
This calculator provides estimates based on standard clinical algorithms. It should not be used as a reliable form of birth control or natural contraception, nor does it replace professional medical advice.
Highest Probability Conception Days
The highest chance of pregnancy occurs on the day of ovulation and the 2 days prior.
Recommended date to take a reliable home urine pregnancy test.
Forecast for Your Next 3 Cycles
| Cycle | Fertile Window | Estimated Ovulation | Next Period |
|---|---|---|---|
| Next Cycle | Nov 26 - Dec 1 | Tue, Dec 1, 2026 | Tue, Dec 15, 2026 |
| In 2 Months | Dec 24 - Dec 29 | Tue, Dec 29, 2026 | Tue, Jan 12, 2027 |
| In 3 Months | Jan 21 - Jan 26 | Tue, Jan 26, 2027 | Tue, Feb 9, 2027 |
How it works
1
Select the first day of your last menstrual period (LMP).
2
Adjust your average menstrual cycle length (default is 28 days, normal range 21–35 days).
3
Review your ovulation date, peak conception days, earliest pregnancy test date, and estimated due date.
Frequently asked questions
When does ovulation occur in a typical cycle?
Ovulation usually occurs approximately 14 days before your next expected period begins. In a standard 28-day cycle, ovulation happens around day 14. In a 32-day cycle, it occurs around day 18.
What days of the cycle have the highest chance of pregnancy?
The highest probability of conception occurs on the day of ovulation and the two days immediately preceding it, as sperm can live up to 5 days inside the female reproductive tract.
Can this calculator be used as natural birth control?
No. Cycle variations due to stress, travel, or hormonal fluctuations make calendar-based tracking unreliable as a primary contraceptive method.
Is this tool free?
Yes. The site is supported by ads, so you never pay or need to create an account.
Does it work on mobile?
Yes. The page adapts to your screen and does not require installing any app.