Ovulation Calculator

First day of last period:

Average cycle length:

Average period length:

Your Fertility Window

Period

Fertile Window

Ovulation

Next Period Starts:

Fertile Window:

Estimated Ovulation Day:

3-Month Calendar

This calculator provides estimates based on your input. Every woman’s cycle is unique, and ovulation can vary each month. The fertile window includes the 5 days before ovulation, the day of ovulation, and possibly the day after. For the most accurate tracking, consider using ovulation tests, basal body temperature tracking, or consulting with a healthcare provider.