Calculate fertile days based on your menstrual cycle.
The Ovulation Calculator predicts the most fertile period based on the length of your menstrual cycle. Ovulation typically occurs 14 days before your next period, with the fertility window being 5–6 days prior to that.
The calculator is completely free, works directly in your browser, and does not store personal information. All calculators on this site use standard formulas; always check the rules that apply where you live.
Ovulation Day ≈ Cycle Day (Cycle Length − 14). Fertility Window: 5 days before – 1 day after ovulation.
Enter your measurements into the calculator fields and press the calculate button – the result will be displayed immediately. You can try different values to compare various scenarios.
Cycle length 30 days, last period started on March 1 → ovulation around March 17 (day 16). Fertility window March 12–18.
The result is an estimate – for precise clinical measurements, consult a healthcare professional.
The calculator is suitable for self-monitoring health, planning workouts, and general health literacy. Tracking values over time provides valuable information about changes in your body.
Remember that a single measurement does not tell the whole story – what matters more is the direction and trend over multiple measurement periods.
Calculate fertile days based on the menstrual cycle. Fill in the requested information in the form, and the ovulation calculator will show the result instantly.
Yes, the ovulation calculator is completely free and does not require registration. All FiksuLaskuri health calculators are free of charge.
No. The calculations are done entirely in your browser and the data you enter is not sent or stored on the server.
No. The ovulation calculator is a rough guide, not a medical diagnosis. For health-related decisions, it is advisable to consult a healthcare professional.
Yes – at the bottom of the page, you can see other calculators related to the same topic that may also interest you.