Ovulation Calculator - Free, Instant, In Your Browser
Estimate your ovulation day and fertile window from the first day of your last period. Fill in the fields and press Calculate to see the result.
How to use Ovulation Calculator
- 1Enter the required date(s) and details above.
- 2Click Calculate - Ovulation Calculator runs instantly, right in your browser.
- 3Read your result below.
Your file is processed in your browser and is never uploaded.
Frequently Asked Questions
Is my data sent to a server?
No - everything runs entirely in your browser with JavaScript. Nothing is uploaded.
Is it free? Do I need an account?
Yes, it is free, and there is nothing to sign up for.
Is this medical advice?
No - it is an estimate based on the numbers you enter, for general information only. Talk to a doctor for personal advice.