Ovulation Calculator

First day of last period: Average cycle length (days):

How to Use the Ovulation Calculator

Enter the first day of your last menstrual period and select your average menstrual cycle length. Click “Calculate Ovulation Date” to find your estimated fertile window and ovulation day.

Understanding Your Ovulation and Fertile Window

Ovulation is when an egg is released from your ovary, typically about 14 days before your next period. This egg can be fertilised for 12 to 24 hours after release. Your fertile window includes the day of ovulation and the five days before it, when sperm can survive in the body, increasing chances of conception.

Frequently Asked Questions (FAQs)

Can I use the calculator if my cycle is irregular?

The calculator works best with regular cycles between 21 and 35 days. If cycles vary greatly, ovulation prediction becomes less precise. Tracking other signs like basal body temperature or using ovulation tests may help.

Why is the average cycle length set to 28 days?

28 days is the most common average cycle length, but cycles can vary. Selecting your actual average cycle length gives more accurate predictions.

Related Concepts

Basal Body Temperature: A slight temperature rise can indicate ovulation.

Luteinizing Hormone (LH): A hormone surge triggers ovulation, which ovulation test kits can detect.

Cervical Mucus: Changes to clearer and stretchier mucus can signal approaching ovulation.