Ovulation Calculator

Track your menstrual cycle, predict ovulation, and identify your fertile window.

Coursera AI Professional CertificateAd
days
Typical cycles are 21-35 days. Average is 28 days.
days
How many days does your period usually last?
Coursera Plus
Ad

Coursera Plus

Unlimited access to 7,000+ world-class courses, hands-on projects, and job-ready certificate programs.

Start Learning
Fertile Window

Enter dates

Your estimated fertile window based on a 28-day cycle

Ovulation

Ovulation Date

-

Next Period

Expected Date

-

Phase

Current Phase

Follicular Phase

Cycle Overview

Menstrual Phase

Days 1-5

Follicular Phase

Days 6-13

Ovulation (Fertile Window)

Days 9-15

Luteal Phase

Days 16-28

Documentation

How Ovulation Tracking Works

Ovulation typically occurs about 14 days before your next period starts. The fertile window spans approximately 6 days: the 5 days before ovulation and the day of ovulation itself.

Important

This calculator provides estimates based on average cycle patterns. For accurate tracking, consider using additional methods like basal body temperature or ovulation predictor kits.

The Calculation

Ovulation Day = Cycle Length − 14
Day 14 = 28 − 14

The luteal phase (after ovulation) is typically 14 days for most women, which is why we subtract 14 from your cycle length to estimate ovulation day.

Last Updated: February 2026

Disclaimer: This calculator is for informational purposes only and should not be used as a contraceptive method or for medical diagnosis. Consult a healthcare provider for personalized fertility advice.

Coursera AI Professional CertificateSponsored
How to Use

About the Ovulation Calculator

What it calculates

This ovulation calculator estimates health and fitness metrics from your personal inputs. Track your menstrual cycle and predict fertile window.

When to use it

Use for personal wellness tracking and education. Consult a healthcare provider for medical advice.

Example

Adjust the inputs above to model your specific scenario with the Ovulation Calculator.

Explore More

Related Calculators

Pregnancy Calculator

Calculate due date and track pregnancy milestones.

Age Calculator

Calculate precise age and days until next birthday.

Anniversary Forecaster

Find out when your 1,000th or 10,000th day together will be.

BAC Calculator

Calculate blood alcohol content based on drinks and body weight.

BMI Calculator

Calculate your Body Mass Index and check weight status.

BMR Calculator

Calculate your Basal Metabolic Rate - calories burned at rest.