Ovulation Calculator

Estimate your ovulation day and fertile window based on your last period and cycle length.

Enter your last period start date and cycle length, then click Calculate
days
Your Estimated Fertility Window
Estimated Ovulation Day
Fertile Window Starts
Fertile Window Ends
Next Expected Period

These are estimates based on average cycle patterns. Actual ovulation timing can vary - consider tracking basal body temperature or using ovulation predictor kits for more precision.

How Ovulation Is Estimated

Ovulation typically occurs about 14 days before your next period begins. This calculator uses your last period start date and average cycle length to estimate your ovulation day, fertile window, and next expected period.

Pair this with our Pregnancy Calculator and Due Date Calculator for further family planning tools.

Frequently Asked Questions

Ovulation typically occurs about 14 days before your next period begins.

It uses your last period start date and average cycle length to estimate your ovulation day, fertile window, and next expected period.

It gives your estimated ovulation day, fertile window, and next expected period.

Yes, it can be paired with a Pregnancy Calculator and Due Date Calculator for further family planning.

Your fertile window is estimated based on your last period start date and average cycle length, centered around your estimated ovulation day.

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