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Ovulation Calculator

Calculate your fertile days and ovulation. For natural family planning.

Updated 2025 Data stays local

Note: These calculations are for informational purposes only and do not replace professional tax or financial advice. All information without guarantee.

Frequently Asked Questions

When does ovulation occur?

Ovulation typically occurs about 14 days before the next period. With a 28-day cycle, that is around day 14. Fertile days span approximately 5 days before ovulation through 1 day after.

How can I determine my fertile days?

Methods include tracking basal body temperature, observing cervical mucus changes, using ovulation test strips, and calendar-based calculation. Combining methods increases accuracy.

What is the Ovulation Calculator?

The ovulation calculator determines the fertile days and expected ovulation date based on cycle length.

How does the Ovulation Calculator work?

Enter the first day of your last period and average cycle length. Ovulation occurs approx. 14 days before the next period. The fertile window is about 5 days before to 1 day after ovulation.

Key Data and Facts

Ovulation: approx. 14 days before next period. Fertile days: 5-6 days per cycle. Average cycle length: 28 days (21-35 normal). Sperm survive up to 5 days.

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