Health & Fitness
Ovulation & Period Calculator
Enter your last period date and cycle length to see your next three cycles, fertile windows and ovulation days.
For information only. Results are estimates and are not medical advice. Please talk to a doctor or qualified professional about your own health.
About the Ovulation & Period Calculator
Ovulation usually happens about 14 days before the next period. The fertile window covers the 5 days before ovulation and the day of ovulation.
This is a prediction, not a contraceptive method. Irregular cycles make predictions less reliable.
Frequently asked questions
Can I use this as birth control?
No. Calendar predictions are not reliable contraception.
What is a normal cycle length?
Between 21 and 35 days is common. Speak to a doctor if your cycles are very irregular or absent.