Ovulation Calculator

Understanding Ovulation

Ovulation is the release of an egg from the ovary, which typically occurs once per menstrual cycle. The egg is viable for fertilization for approximately 12-24 hours after release. However, sperm can survive in the female reproductive tract for up to 5 days, creating a fertile window of about 6 days per cycle.

How This Calculator Works

This calculator uses the calendar method to estimate ovulation:

• Ovulation Day: Calculated as (Cycle Length - Luteal Phase) days after the first day of your last period
• Fertile Window: Spans 5 days before ovulation through 1 day after
• Peak Fertility: The 2 days before ovulation and ovulation day itself

The Menstrual Cycle Phases

Follicular Phase (Days 1-13)

Begins on the first day of menstruation. The pituitary gland releases FSH, stimulating follicle growth in the ovaries. Estrogen levels rise as follicles develop.

Ovulation (Day 14)

A surge in LH triggers the release of a mature egg from the dominant follicle. This typically occurs around day 14 of a 28-day cycle.

Luteal Phase (Days 15-28)

The empty follicle transforms into the corpus luteum, producing progesterone. This phase is relatively consistent at 14 days for most women.

Signs of Ovulation

• Cervical Mucus Changes: Becomes clear, stretchy, and egg-white-like
• Basal Body Temperature Rise: Increases 0.5-1°F after ovulation
• Mittelschmerz: Mild pelvic pain or cramping on one side
• Increased Libido: Natural increase in sexual desire
• Breast Tenderness: Sensitivity due to hormonal changes
• LH Surge: Detectable with ovulation predictor kits

Factors Affecting Ovulation

• Stress and illness
• Travel and time zone changes
• Significant weight changes
• Excessive exercise
• Hormonal imbalances
• Certain medications
• Age (fertility peaks in mid-20s)

Improving Accuracy

For better predictions, consider:

• Track your cycle for several months to determine your average
• Use ovulation predictor kits (OPKs) to detect LH surge
• Monitor basal body temperature daily
• Observe cervical mucus changes
• Consider fertility awareness-based methods