Ovulation Calculator and Fertility Window

Calculate the ovulation day and fertility window based on your last period and cycle length. Discover days of highest conception probability.

Avviso medico: Questo strumento è solo informativo e non sostituisce la consulenza medica. Il calcolo si basa su un ciclo regolare e può essere inaccurato in caso di cicli irregolari, stress, malattie o condizioni ormonali. Per il monitoraggio della fertilità consulta un ginecologo o specialista in medicina della riproduzione.

Calculate Ovulation and Fertile Window

Insert the start date of your last menstrual cycle and average cycle length.

21 giorni28 giorni (media)35 giorni

Enter the date of your last period and cycle length to calculate fertility window.

Come utilizzare Calcolatore Ovulazione e Finestra Fertile

Insert last menstrual period date

Insert the first day of your last menstrual cycle. This is the start date of your period, not the end.

Indicate your cycle duration

Duration of cycle is the number of days from the first day of one period to the first day of the next. The average is 28 days, but cycles between 21 and 35 days are considered regular.

Read the fertile window

The fertile window is composed of 5 days before ovulation plus the day of ovulation (6 days total), which are the days with the highest chance of conception.

Understand the limits of the estimate

Calculation is based on ideal cycle. Ovulation can vary by days due to stress, illness and other factors. For precise monitoring, consider ovulation predictor kits (OPK) or ultrasound.

Suggerimenti

  • Use OPK tests to confirm ovulation timing based on LH peak.
  • Body Basal Temperature (BBT) increases by 0.2-0.5°C after ovulation: track the curve for a few months to learn your personal pattern.
  • Keep a cycle diary for at least 3 months before relying completely on predictions.

Domande frequenti

When does ovulation occur?

Ovulation typically occurs 14 days before the start of the next cycle, regardless of cycle length. For a 28-day cycle, ovulation occurs around day 14. For a 32-day cycle, it occurs around day 18.

What is this fertile window?

The fertile window is the period when it's possible to get pregnant: 5 days before ovulation (for sperm survival) plus the day of ovulation (the egg survives 12-24 hours). Total of 6 days of possible fertility.

How accurate is this calculation?

Calculation assumes regular ovulation based on cycle duration. Stress, illness, weight changes and other factors can shift ovulation by 1-3 days. For greater accuracy, ovulation tests (LH surge) or ultrasound monitoring may be used.

What to do if I have irregular periods?

If your cycle varies by more than 3-4 days from month to month, the calculation is less reliable. Monitor your cycle for at least 3 months, calculate the average duration and use that value. Alternatively, use ovulation tests to confirm the exact time.

Can I become pregnant outside of the fertile window?

The probability is very low but not zero. Sperm can survive in the female reproductive system for up to 5 days. If ovulation occurs before expected, there may be an uncalculated small window.