Understanding the Ovulation Cycle
Ovulation is the release of an egg from one of your ovaries. It usually happens about 14 days before your period starts.
This calculator estimates your most fertile days, which is the timeframe when pregnancy is most likely to occur.
The "fertile window" is the six-day period ending on the day of ovulation. The five days before ovulation, plus the day of ovulation itself,
make up this window. Sperm can survive inside the female reproductive tract for up to five days, so intercourse during this time can result in pregnancy.
How to Use This Calculator
Tracking your cycle is the first step to understanding your fertility.
- Step 1: Enter the first day of your last menstrual period (LMP). This is Day 1 of your cycle.
- Step 2: Enter your average cycle length. This is the number of days from Day 1 of bleeding to Day 1 of your next bleeding.
The average is 28 days, but normal cycles can range from 21 to 35 days.
- Step 3: Review the results. The calculator will show your estimated ovulation date, your fertile window, and the date of your next expected period.
Phases of the Menstrual Cycle
Your cycle is divided into four main phases, as visualized in the chart above.
- Menstruation (Days 1-5): The shedding of the uterine lining. This is when you have your period.
- Follicular Phase (Days 1-13): The body prepares for ovulation. The uterine lining thickens.
- Ovulation (Day 14): The ovary releases an egg. This is the peak of fertility.
- Luteal Phase (Days 15-28): After ovulation, the body produces progesterone to support a potential pregnancy. If pregnancy does not occur, hormone levels drop, and the cycle restarts.
Frequently Asked Questions
How accurate is this calculator?
This calculator uses the "Standard Days Method" based on average cycle statistics. It is about 95% effective if your cycles are always between 26 and 32 days long. However, stress, illness, and diet can shift ovulation, so it is not 100% accurate for every individual.
Can I get pregnant right after my period?
Yes, though it is less likely. If you have a short cycle (e.g., 21 days), you may ovulate just a few days after your period ends. Since sperm can live for 5 days, having sex at the end of your period could lead to pregnancy if you ovulate early.
What are the signs of ovulation?
Common physical signs include a slight increase in basal body temperature, changes in cervical mucus (clear and stretchy, like egg whites), mild pelvic pain (Mittelschmerz), and increased libido.