Estimate your ovulation day and fertile window from your last period and cycle length. Free, private and calculated entirely in your browser.
Ovulation is estimated roughly 14 days before your next period starts, based on the first day of your last period and your average cycle length. The fertile window covers the five days before ovulation plus the day itself.
It is an estimate based on calendar averages. Cycle length varies between people and from month to month, so ovulation tests, basal temperature tracking or a doctor's guidance give a far more precise picture.
No. The dates you enter are used only for the calculation in your browser — nothing is uploaded, saved to an account or shared.
Yes. Ovulation Calculator on Klipza is completely free with no account, no subscription and no watermark on your files, and there is no daily usage limit.
Processing happens locally in your browser wherever technically possible, so your files are not uploaded to a server, stored or shared with third parties.
Yes. It is fully responsive and runs in any modern browser on Android, iPhone, iPad, Windows and macOS — nothing to install.