Ovulation Calculator
Estimate your ovulation day and fertile window.
Result
Results are estimates for general information only and are not professional advice.
Ovulation timing
Ovulation usually happens about 14 days before the next period. This calculator estimates your ovulation day and the fertile window around it from your last period and cycle length. It is an estimate, not a contraceptive method.
Frequently Asked Questions
What is the Ovulation Calculator?
Estimate your ovulation day and fertile window. It runs instantly in your browser and is completely free.
Is the Ovulation Calculator free and does it require signup?
Yes. Every calculator on Calculatis is 100% free with no registration, and the values you enter are never stored.
How accurate is the Ovulation Calculator?
It uses standard, widely-accepted formulas. Results are reliable estimates for general use and are not a substitute for professional advice.